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Author name code: gomory
ADS astronomy entries on 2022-09-14
author:"Gomory, Peter"
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Title: The Solar Activity Monitor Network - SAMNet
Authors: Erdélyi, Robertus; Korsós, Marianna B.; Huang, Xin; Yang,
Yong; Pizzey, Danielle; Wrathmall, Steven A.; Hughes, Ifan G.;
Dyer, Martin J.; Dhillon, Vikram S.; Belucz, Bernadett; Brajša,
Roman; Chatterjee, Piyali; Cheng, Xuewu; Deng, Yuanyong; Domínguez,
Santiago Vargas; Joya, Raúl; Gömöry, Peter; Gyenge, Norbert G.;
Hanslmeier, Arnold; Kucera, Ales; Kuridze, David; Li, Faquan; Liu,
Zhong; Xu, Long; Mathioudakis, Mihalis; Matthews, Sarah; McAteer,
James R. T.; Pevtsov, Alexei A.; Pötzi, Werner; Romano, Paolo; Shen,
Jinhua; Temesváry, János; Tlatov, Andrey G.; Triana, Charles; Utz,
Dominik; Veronig, Astrid M.; Wang, Yuming; Yan, Yihua; Zaqarashvili,
Teimuraz; Zuccarello, Francesca
2022JSWSC..12....2E Altcode:
The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a
future UK-led international network of ground-based solar telescope
stations. SAMNet, at its full capacity, will continuously monitor
the Sun's intensity, magnetic, and Doppler velocity fields at
multiple heights in the solar atmosphere (from photosphere to upper
chromosphere). Each SAMM sentinel will be equipped with a cluster of
identical telescopes each with a different magneto-optical filter (MOFs)
to take observations in K I, Na D, and Ca I spectral bands. A subset
of SAMM stations will have white-light coronagraphs and emission line
coronal spectropolarimeters. The objectives of SAMNet are to provide
observational data for space weather research and forecast. The goal
is to achieve an operationally sufficient lead time of e.g., flare
warning of 2-8 h and provide many sought-after continuous synoptic
maps (e.g., LoS magnetic and velocity fields, intensity) of the lower
solar atmosphere with a spatial resolution limited only by seeing or
diffraction limit, and with a cadence of 10 min. The individual SAMM
sentinels will be connected to their master HQ hub where data received
from all the slave stations will be automatically processed and flare
warning issued up to 26 h in advance.
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Title: Prominence instability and CMEs triggered by massive coronal
rain in the solar atmosphere
Authors: Vashalomidze, Z.; Zaqarashvili, T. V.; Kukhianidze, V.;
Ramishvili, G.; Hanslmeier, A.; Gömöry, P.
2022A&A...658A..18V Altcode: 2021arXiv211001287V
Context. The triggering process for prominence instability
and consequent coronal mass ejections (CMEs) is not fully
understood. Prominences are maintained by the Lorentz force against
the gravity; therefore, reduction of the prominence mass due to the
coronal rain may cause the change of the force balance and hence
destabilisation of the structures. <BR /> Aims: We aim to study the
observational evidence of the influence of coronal rain on the stability
of prominence and subsequent eruption of CMEs. <BR /> Methods: We used
the simultaneous observations from the Atmospheric Imaging Assembly
(AIA) of Solar Dynamics Observatory (SDO) and Sun Earth Connection
Coronal and Heliospheric Investigation (SECHHI) of Solar Terrestrial
Relations Observatory (STEREO) spacecrafts from different angles to
follow the dynamics of prominence and to study the role of coronal rain
in their destabilisation. <BR /> Results: Three different prominences
observed during the years 2011-2012 were analysed using observations
acquired by SDO and STEREO. In all three cases, massive coronal rain
from the prominence body led to the destabilisation of prominence and
subsequently to the eruption of CMEs. The upward rising of prominences
consisted of the slow and fast rise phases. The coronal rain triggered
the initial slow rise of prominences, which led to the final instability
(the fast rise phase) after 18-28 h in all cases. The estimated mass
flux carried by coronal rain blobs showed that the prominences became
unstable after 40% of mass loss. <BR /> Conclusions: We suggest that
the initial slow rise phase was triggered by the mass loss of prominence
due to massive coronal rain, while the fast rise phase (the consequent
instability of prominences) was caused by the torus instability and/or
magnetic reconnection with the overlying coronal field. Therefore, the
coronal rain triggered the instability of prominences and consequent
CMEs. If this is the case, then the coronal rain can be used to predict
the CMEs and hence to improve the space weather predictions.
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Title: Observational evidence for two-component distributions
describing solar magnetic bright points
Authors: Berrios Saavedra, Gerardine; Utz, Dominik; Vargas Domínguez,
Santiago; Campos Rozo, José Iván; González Manrique, Sergio Javier;
Gömöry, Peter; Kuckein, Christoph; Balthasar, Horst; Zelina, Peter
2022A&A...657A..79B Altcode: 2021arXiv211012404B
Context. High-resolution observations of the solar photosphere reveal
the presence of fine structures, in particular the so-called Magnetic
Bright Points (MBPs), which are small-scale features associated with
strong magnetic field regions of the order of kilogauss (kG). It
is especially relevant to study these magnetic elements, which are
extensively detected in all moments during the solar cycle, in order to
establish their contribution to the behavior of the solar atmosphere,
and ultimately a plausible role within the coronal heating problem. <BR
/> Aims: Characterisation of size and velocity distributions of MBPs in
the solar photosphere in two different datasets of quiet Sun images
acquired with high-resolution solar instruments i.e. Solar Optical
Telescope SOT/Hinode and the High-resolution Fast Imager HiFI/GREGOR,
in the G-band (4308 Å). <BR /> Methods: In order to detect the
MBPs, an automatic segmentation and identification algorithm is
used. Next, the identified features were tracked to measure their
proper motions. Finally, a statistical analysis of hundreds of MBPs is
carried out, generating histograms for areas, diameters and horizontal
velocities. <BR /> Results: This work establishes that areas and
diameters of MBPs display log-normal distributions that are well-fitted
by two different components, whereas the velocity vector components
follow Gaussians and the vector magnitude a Rayleigh distribution
revealing again for all vector elements a two component composition. <BR
/> Conclusions: The results can be interpreted as due to the presence of
two different populations of MBPs in the solar photosphere one likely
related to stronger network magnetic flux elements and the other one
to weaker intranetwork flux elemens. In particular this work concludes
on the effect of the different spatial resolution of GREGOR and Hinode
telescopes, affecting detections and average values.
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Title: Properties of the inner penumbra boundary and temporal
evolution of a decaying sunspot (Corrigendum)
Authors: Benko, M.; González Manrique, S. J.; Balthasar, H.; Gömöry,
P.; Kuckein, C.; Jurčák, J.
2021A&A...652C...7B Altcode:
No abstract at ADS
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Title: Evidence For Two-component Distributions Describing Magnetic
Bright Points In The Solar Photosphere
Authors: Vargas Domínguez, S.; Berrios Saavedra, G.; Utz, D.;
Campos Rozo, J. I.; González Manrique, S.; Gömöry, Peter; Kuckein,
Christoph; Balthasar, Horst; Zelina, Peter
2021AAS...23811310V Altcode:
High-resolution observations of the Sun reveal the presence of Magnetic
Bright Points (MBPs), which are small-scale features associated with
strong magnetic field regions, that are found all over the solar
photosphere. In this work, we characterize some physical properties
and dynamics of MBPs in a quiet Sun region by using time series of
images acquired with the High-resolution Fast Imager HiFI/GREGOR and
Solar Optical Telescope SOT/Hinode in the G-band (4308 Angstrom). An
automated segmentation algorithm is used to identify the MBPs and
track their evolution. The results show observational evidence for
two-component distributions of areas, diameters and velocities, that
can be interpreted as corresponding to different populations of MBPs.
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Title: Kink instability of triangular jets in the solar atmosphere
Authors: Zaqarashvili, T. V.; Lomineishvili, S.; Leitner, P.;
Hanslmeier, A.; Gömöry, P.; Roth, M.
2021A&A...649A.179Z Altcode: 2021arXiv210209952Z
Context. It is known that hydrodynamic triangular jets (i.e. the
jet with maximal velocity at its axis, which linearly decreases at
both sides) are unstable to anti-symmetric kink perturbations. The
inclusion of the magnetic field may lead to the stabilisation of the
jets. Jets and complex magnetic fields are ubiquitous in the solar
atmosphere, which suggests the possibility of the kink instability in
certain cases. <BR /> Aims: The aim of the paper is to study the kink
instability of triangular jets sandwiched between magnetic tubes (or
slabs) and its possible connection to observed properties of the jets in
the solar atmosphere. <BR /> Methods: A dispersion equation governing
the kink perturbations is obtained through matching of analytical
solutions at the jet boundaries. The equation is solved analytically
and numerically for different parameters of jets and surrounding
plasma. The analytical solution is accompanied by a numerical simulation
of fully non-linear magnetohydrodynamic (MHD) equations for a particular
situation of solar type II spicules. <BR /> Results: Magnetohydrodynamic
triangular jets are unstable to the dynamic kink instability depending
on the Alfvén Mach number (the ratio of flow to Alfvén speeds) and
the ratio of internal and external densities. When the jet has the
same density as the surrounding plasma, only super-Alfvénic flows are
unstable. However, denser jets are also unstable in a sub-Alfvénic
regime. Jets with an angle to the ambient magnetic field have much
lower thresholds of instability than field-aligned flows. Growth
times of the kink instability are estimated to be 6−15 min for type
I spicules and 5−60 s for type II spicules matching with their
observed lifetimes. The numerical simulation of full non-linear
equations shows that the transverse kink pulse locally destroys
the jet in less than a minute in type II spicule conditions. <BR />
Conclusions: Dynamic kink instability may lead to the full breakdown
of MHD flows and consequently to an observed disappearance of
spicules. <P />Movies associated to Fig. 9 are available at <A
href="https://www.aanda.org/10.1051/0004-6361/202039381/olm">https://www.aanda.org</A>
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Title: Magnetically coupled atmosphere, fast sausage MHD waves, and
forced magnetic field reconnection during the SOL2014-09-10T17:45
flare
Authors: Mészárosová, H.; Gömöry, P.
2020A&A...643A.140M Altcode: 2020arXiv201001527M
<BR /> Aims: We study the physical properties and behaviour of the solar
atmosphere during the GOES X1.6 solar flare on 2014 September 10. <BR
/> Methods: The steady plasma flows and the fast sausage MHD waves
were analysed with the wavelet separation method. The magnetically
coupled atmosphere and the forced magnetic field reconnection were
studied with the help of the Vertical-Current Approximation Non-linear
Force-Free Field code. <BR /> Results: We studied a mechanism of MHD
wave transfer from the photosphere without dissipation or reflection
before reaching the corona and a mechanism of the wave energy
distribution over the solar corona. We report a common behaviour of
(extreme)ultraviolet steady plasma flows (speed of 15.3 → 10.9 km
s<SUP>-1</SUP>) and fast sausage MHD waves (Alfvén speed of 13.7 →
10.3 km s<SUP>-1</SUP> and characteristic periods of 1587 → 1607
s), propagating in cylindrical plasma waveguides of the individual
atmospheric layers (photosphere → corona) observed by SDO/AIA/HMI
and IRIS space instruments. A magnetically coupled solar atmosphere
by a magnetic field flux tube above a sunspot umbra and a magnetic
field reconnection forced by the waves were analysed. The solar
seismology with trapped, leakage, and tunnelled modes of the waves,
dissipating especially in the solar corona, is discussed with respect
to its possible contribution to the outer atmosphere heating. <BR />
Conclusions: We demonstrate that a dispersive nature of fast sausage MHD
waves, which can easily generate the leaky and other modes propagating
outside of their waveguide, and magnetic field flux tubes connecting
the individual atmospheric layers can distribute the magnetic field
energy across the active region. This mechanism can contribute to the
coronal energy balance and to our knowledge on how the coronal heating
is maintained. <P />Movie associated to Fig. 4 is available at <A
href="https://www.aanda.org/10.1051/0004-6361/202038388/olm">https://www.aanda.org</A>
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Title: The dynamics of a solar arch filament system from the
chromosphere to the photosphere
Authors: González Manrique, S. J.; Kuckein, C.; Pastor Yabar, A.;
Diercke, A.; Collados, M.; Gömöry, P.; Zhong, S.; Hou, Y.; Denker, C.
2020sea..confE.199G Altcode:
We study the dynamics of plasma along the legs of an arch filament
system (AFS) from the chromosphere to the photosphere, observed with
high-cadence spectroscopic data from two ground-based solar telescopes:
the GREGOR telescope (Tenerife) using the GREGOR Infrared Spectrograph
in the He I 10830 Å range and the Swedish Solar Telescope (La Palma)
using the CRisp Imaging Spectro-Polarimeter to observe the Ca II 8542
Å and Fe I 6173 Å spectral lines. The temporal evolution of the
draining of the plasma was followed along the legs of a single arch
filament from the chromosphere to the photosphere. The average Doppler
velocities inferred at the upper chromosphere from the He I 10830 Å
triplet reach velocities up to 20-24 km s<SUP>-1</SUP>, and in the lower
chromosphere and upper photosphere the Doppler velocities reach up to
11 km s<SUP>-1</SUP> and 1.5 km s<SUP>-1</SUP> in the case of the Ca II
8542 Å and Si I 10827 Å spectral lines, respectively. The evolution
of the Doppler velocities at different layers of the solar atmosphere
(chromosphere and upper photosphere) shows that they follow the same
line-of-sight (LOS) velocity patern, which confirms the observational
evidence that the plasma drains toward the photosphere as proposed in
models of AFSs. The observations and the nonlinear force-free field
(NLFFF) extrapolations demonstrate that the magnetic field loops of
the AFS rise with time.
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Title: Magnetic Flux Emergence in a Coronal Hole
Authors: Palacios, Judith; Utz, Dominik; Hofmeister, Stefan; Krikova,
Kilian; Gömöry, Peter; Kuckein, Christoph; Denker, Carsten; Verma,
Meetu; González Manrique, Sergio Javier; Campos Rozo, Jose Iván;
Koza, Július; Temmer, Manuela; Veronig, Astrid; Diercke, Andrea;
Kontogiannis, Ioannis; Cid, Consuelo
2020SoPh..295...64P Altcode: 2020arXiv200611779P
A joint campaign of various space-borne and ground-based observatories,
comprising the Japanese Hinode mission (Hinode Observing Plan 338,
20 - 30 September 2017), the GREGOR solar telescope, and the Vacuum
Tower Telescope (VTT), investigated numerous targets such as pores,
sunspots, and coronal holes. In this study, we focus on the coronal
hole region target. On 24 September 2017, a very extended non-polar
coronal hole developed patches of flux emergence, which contributed
to the decrease of the overall area of the coronal hole. These flux
emergence patches erode the coronal hole and transform the area into a
more quiet-Sun-like area, whereby bipolar magnetic structures play an
important role. Conversely, flux cancellation leads to the reduction
of opposite-polarity magnetic fields and to an increase in the area
of the coronal hole.
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Title: Tracking Downflows from the Chromosphere to the Photosphere
in a Solar Arch Filament System
Authors: González Manrique, Sergio Javier; Kuckein, Christoph;
Pastor Yabar, Adur; Diercke, Andrea; Collados, Manuel; Gömöry,
Peter; Zhong, Sihui; Hou, Yijun; Denker, Carsten
2020ApJ...890...82G Altcode: 2020arXiv200107078G
We study the dynamics of plasma along the legs of an arch filament
system (AFS) from the chromosphere to the photosphere, observed with
high-cadence spectroscopic data from two ground-based solar telescopes:
the GREGOR telescope (Tenerife) using the GREGOR Infrared Spectrograph
in the He I 10830 Å range and the Swedish Solar Telescope (La Palma)
using the CRisp Imaging Spectro-Polarimeter to observe the Ca II 8542
Å and Fe I 6173 Å spectral lines. The temporal evolution of the
draining of the plasma was followed along the legs of a single arch
filament from the chromosphere to the photosphere. The average Doppler
velocities inferred at the upper chromosphere from the He I 10830 Å
triplet reach velocities up to 20-24 km s<SUP>-1</SUP>, and in the lower
chromosphere and upper photosphere the Doppler velocities reach up to
11 km s<SUP>-1</SUP> and 1.5 km s<SUP>-1</SUP> in the case of the Ca II
8542 Å and Si I 10827 Å spectral lines, respectively. The evolution
of the Doppler velocities at different layers of the solar atmosphere
(chromosphere and upper photosphere) shows that they follow the same
line-of-sight (LOS) velocity pattern, which confirms the observational
evidence that the plasma drains toward the photosphere as proposed
in models of AFSs. The Doppler velocity maps inferred from the lower
photospheric Ca I 10839 Å or Fe I 6173 Å spectral lines do not
show the same LOS velocity pattern. Thus, there is no evidence that
the plasma reaches the lower photosphere. The observations and the
nonlinear force-free field (NLFFF) extrapolations demonstrate that
the magnetic field loops of the AFS rise with time. We found flow
asymmetries at different footpoints of the AFS. The NLFFF values of
the magnetic field strength help us to explain these flow asymmetries.
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Title: Coordinated observations between China and Europe to follow
active region 12709
Authors: González Manrique, S. J.; Kuckein, C.; Gömöry, P.; Yuan,
S.; Xu, Z.; Rybák, J.; Balthasar, H.; Schwartz, P.
2020IAUS..354...58G Altcode: 2020IAUS..354...58M; 2019arXiv191208611G
We present the first images of a coordinated campaign to follow active
region NOAA 12709 on 2018 May 13 as part of a joint effort between
three observatories (China-Europe). The active region was close to
disk center and enclosed a small pore, a tight polarity inversion line
and a filament in the chromosphere. The active region was observed
with the 1.5-meter GREGOR solar telescope on Tenerife (Spain) with
spectropolarimetry using GRIS in the He i 10830 Å spectral range
and with HiFI using two broad-band filter channels. In addition,
the Lomnicky Stit Observatory (LSO, Slovakia) recorded the same
active region with the new Solar Chromospheric Detector (SCD) in
spectroscopic mode at Hα 6562 Å. The third ground-based telescope
was located at the Fuxian Solar Observatory (China), where the active
region was observed with the 1-meter New Vacuum Solar Telescope
(NVST), using the Multi-Channel High Resolution Imaging System at
Hα 6562 Å. Overlapping images of the active region from all three
telescopes will be shown as well as preliminary Doppler line-of-sight
(LOS) velocities. The potential of such observations are discussed.
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Title: Revisiting the building blocks of solar magnetic fields
by GREGOR
Authors: Utz, Dominik; Kuckein, Christoph; Campos Rozo, Jose Iván;
González Manrique, Sergio Javier; Balthasar, Horst; Gömöry,
Peter; Hernández, Judith Palacios; Denker, Carsten; Verma, Meetu;
Kontogiannis, Ioannis; Krikova, Kilian; Hofmeister, Stefan; Diercke,
Andrea
2020IAUS..354...38U Altcode:
The Sun is our dynamic host star due to its magnetic fields causing
plentiful of activity in its atmosphere. From high energetic flares
and coronal mass ejections (CMEs) to lower energetic phenomena such
as jets and fibrils. Thus, it is of crucial importance to learn about
formation and evolution of solar magnetic fields. These fields cover a
wide range of spatial and temporal scales, starting on the larger end
with active regions harbouring complex sunspots, via isolated pores,
down to the smallest yet resolved elements - so-called magnetic bright
points (MBPs). Here, we revisit the various manifestations of solar
magnetic fields by the largest European solar telescope in operation,
the 1.5-meter GREGOR telescope. We show images from the High-resolution
Fast Imager (HiFI) and spectropolarimetric data from the GREGOR Infrared
Spectrograph (GRIS). Besides, we outline resolved convective features
inside the larger structures - so-called light-bridges occurring on
large to mid-sized scales.
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Title: Science Requirement Document (SRD) for the European Solar
Telescope (EST) (2nd edition, December 2019)
Authors: Schlichenmaier, R.; Bellot Rubio, L. R.; Collados, M.;
Erdelyi, R.; Feller, A.; Fletcher, L.; Jurcak, J.; Khomenko, E.;
Leenaarts, J.; Matthews, S.; Belluzzi, L.; Carlsson, M.; Dalmasse,
K.; Danilovic, S.; Gömöry, P.; Kuckein, C.; Manso Sainz, R.;
Martinez Gonzalez, M.; Mathioudakis, M.; Ortiz, A.; Riethmüller,
T. L.; Rouppe van der Voort, L.; Simoes, P. J. A.; Trujillo Bueno,
J.; Utz, D.; Zuccarello, F.
2019arXiv191208650S Altcode:
The European Solar Telescope (EST) is a research infrastructure
for solar physics. It is planned to be an on-axis solar telescope
with an aperture of 4 m and equipped with an innovative suite of
spectro-polarimetric and imaging post-focus instrumentation. The EST
project was initiated and is driven by EAST, the European Association
for Solar Telescopes. EAST was founded in 2006 as an association
of 14 European countries. Today, as of December 2019, EAST consists
of 26 European research institutes from 18 European countries. The
Preliminary Design Phase of EST was accomplished between 2008 and
2011. During this phase, in 2010, the first version of the EST Science
Requirement Document (SRD) was published. After EST became a project
on the ESFRI roadmap 2016, the preparatory phase started. The goal
of the preparatory phase is to accomplish a final design for the
telescope and the legal governance structure of EST. A major milestone
on this path is to revisit and update the Science Requirement Document
(SRD). The EST Science Advisory Group (SAG) has been constituted by
EAST and the Board of the PRE-EST EU project in November 2017 and has
been charged with the task of providing with a final statement on the
science requirements for EST. Based on the conceptual design, the SRD
update takes into account recent technical and scientific developments,
to ensure that EST provides significant advancement beyond the current
state-of-the-art. The present update of the EST SRD has been developed
and discussed during a series of EST SAG meetings. The SRD develops
the top-level science objectives of EST into individual science
cases. Identifying critical science requirements is one of its main
goals. Those requirements will define the capabilities of EST and the
post-focus instrument suite. The technical requirements for the final
design of EST will be derived from the SRD.
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Title: Observations of a Footpoint Drift of an Erupting Flux Rope
Authors: Zemanová, Alena; Dudík, Jaroslav; Aulanier, Guillaume;
Thalmann, Julia K.; Gömöry, Peter
2019ApJ...883...96Z Altcode: 2019arXiv190802082Z
We analyze the imaging observations of an M-class eruptive flare of 2015
November 4. The pre-eruptive Hα filament was modeled by the nonlinear
force-free field model, which showed that it consisted of two helical
systems. Tether-cutting reconnection involving these two systems led
to the formation of a hot sigmoidal loop structure rooted in a small
hook that formed at the end of the flare ribbon. Subsequently, the hot
loops started to slip away from the small hook until it disappeared. The
loops continued slipping and the ribbon elongated itself by several
tens of arcseconds. A new and larger hook then appeared at the end of
the elongated ribbon with hot and twisted loops rooted there. After
the eruption of these hot loops, the ribbon hook expanded and later
contracted. We interpret these observations in the framework of
the recent three-dimensional (3D) extensions to the standard solar
flare model predicting the drift of the flux rope footpoints. The hot
sigmoidal loop is interpreted as the flux rope, whose footpoints drift
during the eruption. While the deformation and drift of the new hook can
be described by the model, the displacement of the flux rope footpoint
from the filament to that of the erupting flux rope indicate that the
hook evolution can be more complex than those captured by the model.
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Title: Spectroscopy and Differential Emission Measure Diagnostics
of a Coronal Dimming Associated with a Fast Halo CME
Authors: Veronig, Astrid M.; Gömöry, Peter; Dissauer, Karin; Temmer,
Manuela; Vanninathan, Kamalam
2019ApJ...879...85V Altcode: 2019arXiv190601517V
We study the coronal dimming caused by the fast halo CME (deprojected
speed v = 1250 km s<SUP>-1</SUP>) associated with the C3.7 two-ribbon
flare on 2012 September 27, using Hinode/EIS spectroscopy and Solar
Dynamics Observatory (SDO)/AIA Differential Emission Measure (DEM)
analysis. The event reveals bipolar core dimmings encompassed by
hook-shaped flare ribbons located at the ends of the flare-related
polarity inversion line, and marking the footpoints of the erupting
filament. In coronal emission lines of log T [K] = 5.8-6.3, distinct
double-component spectra indicative of the superposition of a stationary
and a fast upflowing plasma component with velocities up to 130 km
s<SUP>-1</SUP> are observed at these regions, which were mapped by the
scanning EIS slit close in time to their impulsive dimming onset. The
outflowing plasma component is found to be of the same order as and
even dominant over the stationary one, with electron densities in the
upflowing component of 2 × 10<SUP>9</SUP> cm<SUP>-3</SUP> at log T
[K] = 6.2. The density evolution in core-dimming regions derived from
SDO/AIA DEM analysis reveals impulsive reductions by 40%-50% within
≲10 minutes and remains at these reduced levels for hours. The
mass-loss rate derived from the EIS spectroscopy in the dimming
regions is of the same order as the mass increase rate observed in the
associated white-light CME (1 × 10<SUP>12</SUP> g s<SUP>-1</SUP>),
indicating that the CME mass increase in the coronagraphic field of
view results from plasma flows from below and not from material piled
up ahead of the outward-moving and expanding CME front.
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Title: Spectropolarimetric Observations of an Arch Filament System
with GREGOR
Authors: Balthasar, H.; Gömöry, P.; González Manrique, S. J.;
Kuckein, C.; Kučera, A.; Schwartz, P.; Berkefeld, T.; Collados, M.;
Denker, C.; Feller, A.; Hofmann, A.; Schlichenmaier, R.; Schmidt,
D.; Schmidt, W.; Sigwarth, M.; Sobotka, M.; Solanki, S. K.; Soltau,
D.; Staude, J.; Strassmeier, K. G.; von der Lühe, O.
2019ASPC..526..217B Altcode: 2018arXiv180401789B
We observed an arch filament system (AFS) in a sunspot group with the
GREGOR Infrared Spectrograph attached to the GREGOR solar telescope. The
AFS was located between the leading sunspot of negative polarity and
several pores of positive polarity forming the following part of the
sunspot group. We recorded five spectro-polarimetric scans of this
region. The spectral range included the spectral lines Si I 1082.7
nm, He I 1083.0 nm, and Ca I 1083.9 nm. In this work we concentrate
on the silicon line which is formed in the upper photosphere. The
line profiles are inverted with the code 'Stokes Inversion based
on Response functions' to obtain the magnetic field vector. The
line-of-sight velocities are determined independently with a Fourier
phase method. Maximum velocities are found close to the ends of AFS
fibrils. These maximum values amount to 2.4 km s<SUP>-1</SUP> next
to the pores and to 4 km s<SUP>-1</SUP> at the sunspot side. Between
the following pores, we encounter an area of negative polarity that
is decreasing during the five scans. We interpret this by new emerging
positive flux in this area canceling out the negative flux. In summary,
our findings confirm the scenario that rising magnetic flux tubes
cause the AFS.
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Title: Pre-eruption Processes: Heating, Particle Acceleration, and the
Formation of a Hot Channel before the 2012 October 20 M9.0 Limb Flare
Authors: Hernandez-Perez, Aaron; Su, Yang; Veronig, Astrid M.;
Thalmann, Julia; Gömöry, Peter; Joshi, Bhuwan
2019ApJ...874..122H Altcode: 2019arXiv190208436H
We report a detailed study of the pre-eruption activities that led to
the occurrence of an M9.0 flare/CME event on 2012 October 20 in NOAA
AR 11598. This includes the study of the preceding confined C2.4 flare
that occurred on the same AR ∼25 minutes earlier. We observed that the
M9.0 flare occurred as a consequence of two distinct triggering events
well separated in time. The first triggering episode occurred as early
as ∼20 minutes before the onset of the M9.0 flare, evidenced by the
destabilization and rise of a pre-existing filament to a new position of
equilibrium at a higher coronal altitude during the decay phase of the
C2.4 flare. This brought the system to a magnetic configuration where
the establishment of the second triggering event was favorable. The
second triggering episode occurred ∼17 minutes later, during the
early phase of the M9.0 flare, evidenced by the further rise of the
filament and successful ejection. The second trigger is followed by a
flare precursor phase, characterized by nonthermal emission and the
sequential formation of a hot channel as shown by the SDO/AIA DEM
(differential emission measure) maps, the RHESSI X-ray images and
spectra. These observations are suggestive of magnetic reconnection
and particle acceleration that can explain the precursor phase and can
be directly related to the formation of the hot channel. We discuss
the triggering mechanisms, their implications during the early and
precursor phases and highlight the importance of early activities and
preceding small confined flares to understand the initiation of large
eruptive flares.
---------------------------------------------------------
Title: Properties of the inner penumbral boundary and temporal
evolution of a decaying sunspot
Authors: Benko, M.; González Manrique, S. J.; Balthasar, H.; Gömöry,
P.; Kuckein, C.; Jurčák, J.
2018A&A...620A.191B Altcode: 2018arXiv181013185B
Context. It has been empirically determined that the umbra-penumbra
boundaries of stable sunspots are characterized by a constant value of
the vertical magnetic field. <BR /> Aims: We analyzed the evolution
of the photospheric magnetic field properties of a decaying sunspot
belonging to NOAA 11277 between August 28-September 3, 2011. The
observations were acquired with the spectropolarimeter on-board of
the Hinode satellite. We aim to prove the validity of the constant
vertical magnetic-field boundary between the umbra and penumbra in
decaying sunspots. <BR /> Methods: A spectral-line inversion technique
was used to infer the magnetic field vector from the full-Stokes
profiles. In total, eight maps were inverted and the variation of
the magnetic properties in time were quantified using linear or
quadratic fits. <BR /> Results: We find a linear decay of the umbral
vertical magnetic field, magnetic flux, and area. The penumbra showed
a linear increase of the vertical magnetic field and a sharp decay
of the magnetic flux. In addition, the penumbral area quadratically
decayed. The vertical component of the magnetic field is weaker on the
umbra-penumbra boundary of the studied decaying sunspot compared to
stable sunspots. Its value seem to be steadily decreasing during the
decay phase. Moreover, at any time of the sunspot decay shown, the inner
penumbra boundary does not match with a constant value of the vertical
magnetic field, contrary to what is seen in stable sunspots. <BR />
Conclusions: During the decaying phase of the studied sunspot, the
umbra does not have a sufficiently strong vertical component of the
magnetic field and is thus unstable and prone to be disintegrated by
convection or magnetic diffusion. No constant value of the vertical
magnetic field is found for the inner penumbral boundary.
---------------------------------------------------------
Title: Temporal evolution of arch filaments as seen in He I 10 830 Å
Authors: González Manrique, S. J.; Kuckein, C.; Collados, M.; Denker,
C.; Solanki, S. K.; Gömöry, P.; Verma, M.; Balthasar, H.; Lagg,
A.; Diercke, A.
2018A&A...617A..55G Altcode: 2018arXiv180700728G
<BR /> Aims: We study the evolution of an arch filament system (AFS)
and of its individual arch filaments to learn about the processes
occurring in them. <BR /> Methods: We observed the AFS at the
GREGOR solar telescope on Tenerife at high cadence with the very
fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS)
in the He I 10 830 Å spectral range. The He I triplet profiles
were fitted with analytic functions to infer line-of-sight (LOS)
velocities to follow plasma motions within the AFS. <BR /> Results:
We tracked the temporal evolution of an individual arch filament
over its entire lifetime, as seen in the He I 10 830 Å triplet. The
arch filament expanded in height and extended in length from 13″ to
21″. The lifetime of this arch filament is about 30 min. About 11
min after the arch filament is seen in He I, the loop top starts to
rise with an average Doppler velocity of 6 km s<SUP>-1</SUP>. Only two
minutes later, plasma drains down with supersonic velocities towards
the footpoints reaching a peak velocity of up to 40 km s<SUP>-1</SUP>
in the chromosphere. The temporal evolution of He I 10 830 Å profiles
near the leading pore showed almost ubiquitous dual red components of
the He I triplet, indicating strong downflows, along with material
nearly at rest within the same resolution element during the whole
observing time. <BR /> Conclusions: We followed the arch filament as it
carried plasma during its rise from the photosphere to the corona. The
material then drained toward the photosphere, reaching supersonic
velocities, along the legs of the arch filament. Our observational
results support theoretical AFS models and aids in improving future
models. <P />The movie associated to Fig. 3 is available at <A
href="https://www.aanda.org/10.1051/0004-6361/201832684/olm">https://www.aanda.org/</A>
---------------------------------------------------------
Title: Dynamcis and magnetic properties in coronal holes using
high-resolution multi-instrument solar observations
Authors: Krikova, K.; Utz, D.; Veronig, A.; Gömöry, P.; Hofmeister,
S.; Temmer, M.
2018simi.conf...31K Altcode:
Using high-resolution solar observations from the Hinode Instruments
SOT/SP, EIS and XRT as well as IRIS from a coronal hole on the 26th of
September 2017, we are investigating the dynamics within the coronal
hole visible on the specified date. Further satellite data support is
given by full disc images from SDO with the AIA and HMI instruments. EIS
and IRIS data provide us with crucial information about the plasma and
energy flow from the Sun's chromosphere into the corona using the EUV
and UV spectra and images. Investigating the magnetic configuration
as well as the dynamics and changes within the coronal hole by using
the SOT/SP data will give us additional crucial insights about the
physical processes leading to the corresponding changes in the higher
atmosphere. We compare the Hinode data with AIA and HMI data to get
a firm comprehensive picture about the connection from high resolved
photospheric fields and its dynamics within the higher layer. Within the
timeframe of the analysed EIS dataset two microflare events associated
with a solar jet were captured, originating inside the coronal hole
under investigation. We believe that it is totally worthwhile to study
these features in full detail as not so much attention was paid to high
energy processes within coronal holes and their basic relationship to
the harboring coronal hole and they show surprisingly high downflows
in the Fe XII iron line (up to 140 km/s). In the current proceeding
we will outline the state of the art of this investigation and give
an overview of the further steps necessary. The mentioned data were
obtained during a recent GREGOR campaign with the joint support of
IRIS and Hinode (HOP 338).
---------------------------------------------------------
Title: Small-scale dynamcis in a coronal-hole related to microflaring
events
Authors: Krikova, K.; Utz, D.; Veronig, A.; Hofmeister, S.; Temmer,
M.; Gömöry, P.; Holzknecht, L.
2018CEAB...42....8K Altcode:
Using high-resolution solar imagery and spectroscopy from the Hinode
EIS and SDO instruments, we investigate the dynamics within a coronal
hole observed on the 26th September 2017. Further data is given by
full disc images from SDO with the AIA and HMI instruments. EIS
spectra provide us with crucial information about the plasma and
energy flows from the Sun's chromosphere into the corona. Within the
timeframe of the analysed EIS dataset two microflares associated with a
jet-like event were captured, originating inside the coronal hole under
investigation. These two microflare events were analysed in the study at
hand in detail. Such recurring solar transient events could contribute
to the mass and energy input into the solar corona and also to the solar
wind. Our analysis shows that microflare temperatures can reach up to
3 MK with a hot component close to the reconnection site. Moreover an
enhanced density at the microflare region was found. The obtained EIS
ion line ratios suggest a density of up to 2.9 \cdot 10^{10} cm^{-3}.
---------------------------------------------------------
Title: Generation Mechanisms of Quasi-parallel and Quasi-circular
Flare Ribbons in a Confined Flare
Authors: Hernandez-Perez, Aaron; Thalmann, Julia K.; Veronig, Astrid
M.; Su, Yang; Gömöry, Peter; Dickson, Ewan C.
2017ApJ...847..124H Altcode: 2017arXiv170808612H
We analyze a confined multiple-ribbon M2.1 flare (SOL2015-01-29T11:42)
that originated from a fan-spine coronal magnetic field configuration,
within active region NOAA 12268. The observed ribbons form in
two steps. First, two primary ribbons form at the main flare site,
followed by the formation of secondary ribbons at remote locations. We
observe a number of plasma flows at extreme-ultraviolet temperatures
during the early phase of the flare (as early as 15 minutes before
the onset) propagating toward the formation site of the secondary
ribbons. The secondary ribbon formation is co-temporal with the
arrival of the pre-flare generated plasma flows. The primary ribbons
are co-spatial with Ramaty High Energy Spectroscopic Imager (RHESSI)
hard X-ray sources, whereas no enhanced X-ray emission is detected at
the secondary ribbon sites. The (E)UV emission, associated with the
secondary ribbons, peaks ∼1 minute after the last RHESSI hard X-ray
enhancement. A nonlinear force-free model of the coronal magnetic field
reveals that the secondary flare ribbons are not directly connected to
the primary ribbons, but to regions nearby. Detailed analysis suggests
that the secondary brightenings are produced due to dissipation of
kinetic energy of the plasma flows (heating due to compression), and
not due to non-thermal particles accelerated by magnetic reconnection,
as is the case for the primary ribbons.
---------------------------------------------------------
Title: Flows along arch filaments observed in the GRIS `very fast
spectroscopic mode'
Authors: González Manrique, S. J.; Denker, C.; Kuckein, C.; Pastor
Yabar, A.; Collados, M.; Verma, M.; Balthasar, H.; Diercke, A.;
Fischer, C. E.; Gömöry, P.; Bello González, N.; Schlichenmaier,
R.; Cubas Armas, M.; Berkefeld, T.; Feller, A.; Hoch, S.; Hofmann,
A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Schmidt, D.; Schmidt,
W.; Sigwarth, M.; Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude,
J.; Strassmeier, K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2017IAUS..327...28G Altcode: 2017arXiv170102206G
A new generation of solar instruments provides improved spectral,
spatial, and temporal resolution, thus facilitating a better
understanding of dynamic processes on the Sun. High-resolution
observations often reveal multiple-component spectral line profiles,
e.g., in the near-infrared He i 10830 Å triplet, which provides
information about the chromospheric velocity and magnetic fine
structure. We observed an emerging flux region, including two small
pores and an arch filament system, on 2015 April 17 with the `very
fast spectroscopic mode' of the GREGOR Infrared Spectrograph (GRIS)
situated at the 1.5-meter GREGOR solar telescope at Observatorio del
Teide, Tenerife, Spain. We discuss this method of obtaining fast (one
per minute) spectral scans of the solar surface and its potential to
follow dynamic processes on the Sun. We demonstrate the performance
of the `very fast spectroscopic mode' by tracking chromospheric
high-velocity features in the arch filament system.
---------------------------------------------------------
Title: Spectral Characteristics of the He I D<SUB>3</SUB> Line in
a Quiescent Prominence Observed by THEMIS
Authors: Koza, Július; Rybák, Ján; Gömöry, Peter; Kozák, Matúš;
López Ariste, Arturo
2017SoPh..292...98K Altcode: 2017arXiv171209255K
We analyze the observations of a quiescent prominence acquired by
the Téléscope Heliographique pour l'Étude du Magnetisme et des
Instabilités Solaires (THEMIS) in the He I 5876 Å (He I D<SUB>3</SUB>)
multiplet aiming to measure the spectral characteristics of the He
I D<SUB>3</SUB> profiles and to find for them an adequate fitting
model. The component characteristics of the He I D<SUB>3</SUB> Stokes I
profiles are measured by the fitting system by approximating them with
a double Gaussian. This model yields an He I D<SUB>3</SUB> component
peak intensity ratio of 5.5 ±0.4 , which differs from the value of
8 expected in the optically thin limit. Most of the measured Doppler
velocities lie in the interval ± 5 km s<SUP>−1</SUP>, with a standard
deviation of ± 1.7 km s<SUP>−1</SUP> around the peak value of 0.4
km s<SUP>−1</SUP>. The wide distribution of the full-width at half
maximum has two maxima at 0.25 Å and 0.30 Å for the He I D<SUB>3</SUB>
blue component and two maxima at 0.22 Å and 0.31 Å for the red
component. The width ratio of the components is 1.04 ±0.18 . We show
that the double-Gaussian model systematically underestimates the blue
wing intensities. To solve this problem, we invoke a two-temperature
multi-Gaussian model, consisting of two double-Gaussians, which
provides a better representation of He I D<SUB>3</SUB> that is free
of the wing intensity deficit. This model suggests temperatures of
11.5 kK and 91 kK, respectively, for the cool and the hot component
of the target prominence. The cool and hot components of a typical He
I D<SUB>3</SUB> profile have component peak intensity ratios of 6.6
and 8, implying a prominence geometrical width of 17 Mm and an optical
thickness of 0.3 for the cool component, while the optical thickness of
the hot component is negligible. These prominence parameters seem to
be realistic, suggesting the physical adequacy of the multi-Gaussian
model with important implications for interpreting He I D<SUB>3</SUB>
spectropolarimetry by current inversion codes.
---------------------------------------------------------
Title: Flare-induced changes of the photospheric magnetic field in
a δ-spot deduced from ground-based observations
Authors: Gömöry, P.; Balthasar, H.; Kuckein, C.; Koza, J.;
Veronig, A. M.; González Manrique, S. J.; Kučera, A.; Schwartz,
P.; Hanslmeier, A.
2017A&A...602A..60G Altcode: 2017arXiv170406089G
<BR /> Aims: Changes of the magnetic field and the line-of-sight
velocities in the photosphere are being reported for an M-class
flare that originated at a δ-spot belonging to active region NOAA
11865. <BR /> Methods: High-resolution ground-based near-infrared
spectropolarimetric observations were acquired simultaneously in
two photospheric spectral lines, Fe I 10783 Å and Si I 10786 Å,
with the Tenerife Infrared Polarimeter at the Vacuum Tower Telescope
(VTT) in Tenerife on 2013 October 15. The observations covered several
stages of the M-class flare. Inversions of the full-Stokes vector of
both lines were carried out and the results were put into context using
(extreme)-ultraviolet filtergrams from the Solar Dynamics Observatory
(SDO). <BR /> Results: The active region showed high flaring activity
during the whole observing period. After the M-class flare, the
longitudinal magnetic field did not show significant changes along
the polarity inversion line (PIL). However, an enhancement of the
transverse magnetic field of approximately 550 G was found that
bridges the PIL and connects umbrae of opposite polarities in the
δ-spot. At the same time, a newly formed system of loops appeared
co-spatially in the corona as seen in 171 Å filtergrams of the
Atmospheric Imaging Assembly (AIA) on board SDO. However, we cannot
exclude that the magnetic connection between the umbrae already existed
in the upper atmosphere before the M-class flare and became visible
only later when it was filled with hot plasma. The photospheric
Doppler velocities show a persistent upflow pattern along the PIL
without significant changes due to the flare. <BR /> Conclusions:
The increase of the transverse component of the magnetic field after
the flare together with the newly formed loop system in the corona
support recent predictions of flare models and flare observations. <P
/>The movie associated to Figs. 4 and 5 is available at <A
href="http://www.aanda.org/10.1051/0004-6361/201730644/olm">http://www.aanda.org</A>
---------------------------------------------------------
Title: Understanding CMEs using plasma diagnostics of the related
dimmings
Authors: Vanninathan, Kamalam; Veronig, Astrid; Gomory, Peter;
Dissauer, Karin; Temmer, Manuela; Hannah, Iain; Kontar, Eduard
2017EGUGA..19.1571V Altcode:
Coronal Mass Ejections (CMEs) are often associated with dimmings that
are well observed in Extreme Ultra-violet (EUV) wavelengths. Such
dimmings are suggested to represent the evacuation of mass that is
carried out by CMEs and are a unique and indirect means to study CME
properties. While Earth-directed CMEs (on-disk CMEs) are difficult to
observe due to the bright background solar disk and projection effects,
their corresponding dimmings are clearly discernible and ideally suited
for analysis. Using data from the 6 EUV channels of Solar Dynamics
Observatory/Atmospheric Imaging Assembly for Differential Emission
Measure (DEM) diagnostics, we determine the plasma characteristics of
the dimming region. These data are well suited for this kind of study
due to the good temperature ranges covered by the multiple passbands
of the instrument. We analyse 7 on-disk and 5 off-limb events and
derive the weighted density and temperature as a function of time,
from the DEMs. From such an analysis we differentiate 2 types of dimming
regions: core and secondary dimmings. Core dimmings often occur in pairs
lying on either sides of the active region and in opposite polarity
regions while the secondary dimming is more extended. In both the
regions the derived plasma parameters reach a minimum within 30-60
min after the flare. For each event the core dimming region shows
a higher decrease in density and temperature than the corresponding
secondary dimming regions. The values of these parameters remains low
within the core dimming region for the entire duration of this study
( 10 hrs after the flare) while the secondary dimming region starts to
show a gradual increase after 1-2 hrs. We also use spectroscopic data
from Hinode/Extreme-Ultraviolet Imaging Spectrometer to differentiate
core and secondary dimming regions. We find that the Fe XIII 202 Å
line shows double component profiles within the core dimming region
with strong blueshifts of 100 km/s while the secondary dimming region
has weak upflows of 10 km/s. We conclude that the core dimming region
corresponds to footpoints of the erupting flux rope from where there
is continuous strong upflowing plasma for at least 10 hrs after the
flare, while the secondary dimming region begins to refill within 1-2
hrs. These measurements can be used to deduce information about the
mass of on-disk CMEs where white light measurements can fail. We also
confirm that the dimmings are mainly caused by density decrease and
not temperature changes. DEM analysis is a strong tool to decipher
CME properties from dimming regions.
---------------------------------------------------------
Title: Flare induced changes of the photospheric magnetic field in
a delta-spot deduced from ground-based observations
Authors: Gömöry, P.; Balthasar, H.; Kuckein, C.; Koza, J.;
Kuĉera, A.; González Manrique, S. J.; Schwartz, P.; Veronig, A. M.;
Hanslmeier, A.
2017psio.confE.107G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: NLTE modeling of a small active region filament observed with
the VTT
Authors: Schwartz, P.; Balthasar, H.; Kuckein, C.; Koza, J.; Gömöry,
P.; Rybák, J.; Heinzel, P.; Kučera, A.
2016AN....337.1045S Altcode:
An active region mini-discretionary-filament was observed with the
Vacuum Tower Telescope (VTT) in Tenerife simultaneously in the He
I infrared triplet using the Tenerife Infrared Polarimeter 1 (TIP
1), in Hα with the TESOS Fabry-Pérot interferometer, and in Ca II
8542 Å with the VTT spectrograph. The spectropolarimetric data were
inverted using the HAZEL code and Hα profiles were modelled by solving
a NLTE radiative transfer in a simple isobaric and isothermal 2D slab
irradiated both from its bottom and sides from the solar surface. It was
found that the mini-discretionary-filament is composed of horizontal
fluxtubes, along which the cool plasma of T∼10 000 K can flow with
very large, even supersonic, velocities.
---------------------------------------------------------
Title: Spectropolarimetric observations of an arch filament system
with the GREGOR solar telescope
Authors: Balthasar, H.; Gömöry, P.; González Manrique, S. J.;
Kuckein, C.; Kavka, J.; Kučera, A.; Schwartz, P.; Vašková, R.;
Berkefeld, T.; Collados Vera, M.; Denker, C.; Feller, A.; Hofmann,
A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Pastor Yabar, A.;
Rezaei, R.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth,
M.; Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier,
K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016AN....337.1050B Altcode: 2016arXiv160901514B
Arch filament systems occur in active sunspot groups, where a fibril
structure connects areas of opposite magnetic polarity, in contrast to
active region filaments that follow the polarity inversion line. We
used the GREGOR Infrared Spectrograph (GRIS) to obtain the full
Stokes vector in the spectral lines Si I λ1082.7 nm, He I λ1083.0
nm, and Ca I λ1083.9 nm. We focus on the near-infrared calcium line
to investigate the photospheric magnetic field and velocities, and
use the line core intensities and velocities of the helium line to
study the chromospheric plasma. The individual fibrils of the arch
filament system connect the sunspot with patches of magnetic polarity
opposite to that of the spot. These patches do not necessarily coincide
with pores, where the magnetic field is strongest. Instead, areas are
preferred not far from the polarity inversion line. These areas exhibit
photospheric downflows of moderate velocity, but significantly higher
downflows of up to 30 km s<SUP>-1</SUP> in the chromospheric helium
line. Our findings can be explained with new emerging flux where the
matter flows downward along the field lines of rising flux tubes,
in agreement with earlier results.
---------------------------------------------------------
Title: Fitting peculiar spectral profiles in He I 10830Å absorption
features
Authors: González Manrique, S. J.; Kuckein, C.; Pastor Yabar, A.;
Collados, M.; Denker, C.; Fischer, C. E.; Gömöry, P.; Diercke, A.;
Bello González, N.; Schlichenmaier, R.; Balthasar, H.; Berkefeld, T.;
Feller, A.; Hoch, S.; Hofmann, A.; Kneer, F.; Lagg, A.; Nicklas, H.;
Orozco Suárez, D.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Sobotka,
M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier, K. G.; Verma,
M.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016AN....337.1057G Altcode: 2016arXiv160300679G
The new generation of solar instruments provides better
spectral, spatial, and temporal resolution for a better
understanding of the physical processes that take place on the
Sun. Multiple-component profiles are more commonly observed with these
instruments. Particularly, the He I 10830 Å triplet presents such
peculiar spectral profiles, which give information on the velocity
and magnetic fine structure of the upper chromosphere. The purpose
of this investigation is to describe a technique to efficiently fit
the two blended components of the He I 10830 Å triplet, which are
commonly observed when two atmospheric components are located within
the same resolution element. The observations used in this study were
taken on 2015 April 17 with the very fast spectroscopic mode of the
GREGOR Infrared Spectrograph (GRIS) attached to the 1.5-m GREGOR solar
telescope, located at the Observatorio del Teide, Tenerife, Spain. We
apply a double-Lorentzian fitting technique using Levenberg-Marquardt
least-squares minimization. This technique is very simple and much
faster than inversion codes. Line-of-sight Doppler velocities can
be inferred for a whole map of pixels within just a few minutes. Our
results show sub- and supersonic downflow velocities of up to 32 km
s<SUP>-1</SUP> for the fast component in the vicinity of footpoints of
filamentary structures. The slow component presents velocities close
to rest.
---------------------------------------------------------
Title: Broadband microwave sub-second pulsations in an expanding
coronal loop of the 2011 August 10 flare
Authors: Mészárosová, H.; Rybák, J.; Kashapova, L.; Gömöry,
P.; Tokhchukova, S.; Myshyakov, I.
2016A&A...593A..80M Altcode: 2016arXiv160904217M
<BR /> Aims: We studied the characteristic physical properties and
behavior of broadband microwave sub-second pulsations observed in
an expanding coronal loop during the GOES C2.4 solar flare on 2011
August 10. <BR /> Methods: The complex microwave dynamic spectrum and
the expanding loop images were analyzed with the help of SDO/AIA/HMI,
RHESSI, and the STEREO/SECCHI-EUVI data processing software, wavelet
analysis methods, the GX Simulator tool, and the NAFE method. <BR />
Results: We found sub-second pulsations and other different burst
groups in the complex radio spectrum. The broadband (bandwidth about
1 GHz) sub-second pulsations (temporal period range 0.07-1.49 s,
no characteristic dominant period) lasted 70 s in the frequency
range 4-7 GHz. These pulsations were not correlated at their
individual frequencies, had no measurable frequency drift, and zero
polarization. In these pulsations, we found the signatures of fast
sausage magnetoacoustic waves with the characteristic periods of 0.7
and 2 s. The other radio bursts showed their characteristic frequency
drifts in the range of -262-520 MHz s<SUP>-1</SUP>. They helped us to
derive average values of 20-80 G for the coronal magnetic field strength
in the place of radio emission. It was revealed that the microwave
event belongs to an expanding coronal loop with twisted sub-structures
observed in the 131, 94, and 193 Å SDO/AIA channels. Their slit-time
diagrams were compared with the location of the radio source at 5.7 GHz
to realize that the EUV intensity of the expanding loop increased just
before the radio source triggering. We reveal two EUV bidirectional
flows that are linked with the start time of the loop expansion. Their
positions were close to the radio source and propagated with velocities
within a range of 30-117 km s<SUP>-1</SUP>. <BR /> Conclusions: We
demonstrate that periodic regime of the electron acceleration in a model
of the quasi-periodic magnetic reconnection might be able to explain
physical properties and behavior of the sub-second pulsations. The
depolarization process of the microwave emission might be caused by
a plasma turbulence in the radio source. Finally, the observed EUV
flows might be linked with reconnection outflows.
---------------------------------------------------------
Title: Chromospheric evaporation flows and density changes deduced
from Hinode/EIS during an M1.6 flare
Authors: Gömöry, P.; Veronig, A. M.; Su, Y.; Temmer, M.; Thalmann,
J. K.
2016A&A...588A...6G Altcode: 2016arXiv160202145G
<BR /> Aims: We study the response of the solar atmosphere during a GOES
M1.6 flare using spectroscopic and imaging observations. In particular,
we examine the evolution of the mass flows and electron density together
with the energy input derived from hard X-ray (HXR) in the context of
chromospheric evaporation. <BR /> Methods: We analyzed high-cadence
sit-and-stare observations acquired with the Hinode/EIS spectrometer
in the Fe xiii 202.044 Å (log T = 6.2) and Fe xvi 262.980 Å (log T =
6.4) spectral lines to derive temporal variations of the line intensity,
Doppler shifts, and electron density during the flare. We combined these
data with HXR measurements acquired with RHESSI to derive the energy
input to the lower atmosphere by flare-accelerated electrons. <BR />
Results: During the flare impulsive phase, we observe no significant
flows in the cooler Fe xiii line but strong upflows, up to 80-150 km
s<SUP>-1</SUP>, in the hotter Fe xvi line. The largest Doppler shifts
observed in the Fe xvi line were co-temporal with the sharp intensity
peak. The electron density obtained from a Fe xiii line pair ratio
exhibited fast increase (within two minutes) from the pre-flare level
of 5.01 × 10<SUP>9</SUP> cm<SUP>-3</SUP> to 3.16 × 10<SUP>10</SUP>
cm<SUP>-3</SUP> during the flare peak. The nonthermal energy flux
density deposited from the coronal acceleration site to the lower
atmospheric layers during the flare peak was found to be 1.34 ×
10<SUP>10</SUP> erg s<SUP>-1</SUP> cm<SUP>-2</SUP> for a low-energy
cut-off that was estimated to be 16 keV. During the decline flare phase,
we found a secondary intensity and density peak of lower amplitude
that was preceded by upflows of ~15 km s<SUP>-1</SUP> that were
detected in both lines. The flare was also accompanied by a filament
eruption that was partly captured by the EIS observations. We derived
Doppler velocities of 250-300 km s<SUP>-1</SUP> for the upflowing
filament material. <BR /> Conclusions: The spectroscopic results
for the flare peak are consistent with the scenario of explosive
chromospheric evaporation, although a comparatively low value of the
nonthermal energy flux density was determined for this phase of the
flare. This outcome is discussed in the context of recent hydrodynamic
simulations. It provides observational evidence that the response
of the atmospheric plasma strongly depends on the properties of the
electron beams responsible for the heating, in particular the steepness
of the energy distribution. The secondary peak of line intensity and
electron density detected during the decline phase is interpreted as a
signature of flare loops being filled by expanding hot material that
is due to chromospheric evaporation. <P />A movie is available at <A
href="http://www.aanda.org/10.1051/0004-6361/201527403/olm">http://www.aanda.org</A>
---------------------------------------------------------
Title: Non-LTE Inversion of Spectropolarimetric and Spectroscopic
Observations of a Small Active-region Filament Observed at the VTT
Authors: Schwartz, P.; Balthasar, H.; Kuckein, C.; Koza, J.; Gömöry,
P.; Rybák, J.; Kučera, A.; Heinzel, P.
2016ASPC..504..205S Altcode:
An active region mini-filament was observed by VTT simultaneously
in the He<small>I</small> 10 830 Å triplet by the TIP 1
spectropolarimeter, in Hα by the TESOS Fabry-Pérot interferometer, and
in Ca <small>II</small> 8542 Å by the VTT spectrograph. The
spectropolarimetric data were inverted using the HAZEL code and Hα
profiles were modelled solving a NLTE radiative transfer in a simple
isobaric and isothermal 2D slab irradiated both from bottom and
sides. It was found that the mini-filament is composed of horizontal
fluxtubes, along which the cool plasma of T∼10 000 K can flow by
very large - even supersonic - velocities.
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Title: The CoMP-S Instrument at the Lomnický Peak Observatory:
Status Report
Authors: Kučera, A.; Ambróz, J.; Gömöry, P.; Habaj, P.; Kavka,
J.; Kozák, M.; Schwartz, P.; Rybák, J.; Tomczyk, S.; Sewell, S.;
Aumiller, P.; Summers, R.; Watt, A.
2016ASPC..504..321K Altcode:
The Coronal Multi-channel Polarimeter for Slovakia (CoMP-S) has
been installed at the high-altitude Lomnicky Peak Observatory of the
Astronomical Institute of SAS (2633 m a.s.l.) in 2011. The instrument
was designed and manufactured by HAO/NCAR (Boulder, USA) with a
tunable Lyot filter and polarimeter for visible and near IR spectral
regions. This instrument is proposed for coronagraphic observations of
magnetic and velocity fields in the solar corona and in prominences. A
fundamental upgrade of this instrument has been prepared with pair
of cameras sensitive in the near IR spectral region in a new camera
module. This upgrade is being incorporated to the instrument in course
of the year 2014. In this contribution the technical parameters of the
final configuration of the CoMP-S instrument containing four cameras,
covering both visible and near IR spectral regions, are described. We
also present a potential of the CoMP-S instrument for coronagraphic
spectro-polarimetric observations of the solar corona and prominences
with a capability for sequential measurements of the spectral profiles
of all prominent emission lines in spectral region from 500 to 1100 nm.
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Title: Dual instrument for Flare and CME onset observations -
Double solar Coronagraph with Solar Chromospheric Detector and
Coronal Multi-channel Polarimeter at Lomnicky stit Observatory
Authors: Kucera, Ales; Tomczyk, Steven; Rybak, Jan; Sewell, Scott;
Gomory, Peter; Schwartz, Pavol; Ambroz, Jaroslav; Kozak, Matus
2015IAUGA..2246687K Altcode:
We report on unique dual instrument developed for simultaneous
measurements of velocity and magnetic fields in the solar chromosphere
and corona. We describe the technical parameters and capability of
the Coronal Multi-channel Polarimeter (CoMP-S) and Solar Chromospheric
detector (SCD) mounted at the Double solar coronagraph at Lomnicky Stit
Observatory and working simultaneously with strictly parallel pointing
of both coronagraphs. The CoMP-S is 2D spectropolarimeter designed
for observations of VIS and near-IR emission lines of prominences
and corona with operating spectral range: 500 - 1100 nm, sequential
measurement of several VIS and near-IR lines. Its field of view is
14 arcmin x 11 arcmin. It consists of 4-stage calcite Lyot filter
followed by the ferro-liquid crystal polarizer and four cameras (2
visible, 2 infrared). The capability is to deliver 2D full Stokes I,
Q, U, V, using registration with 2 IR cameras (line + background) and
2 VIS cameras (line + background) SCD is a single beam instrument to
observe bright chromosphere. It is a combination of tunable filter and
polarimeter. Spectral resolution of the SCD ranges from 0.046 nm for
observations of the HeI 1083 nm line up to to 25 pm is for observation
of the HeI 587.6 nm line. The birefringent filter of the SCD has high
spectral resolution, as well as spatial resolution (1.7 arcseconds)
and temporal resolution (10 seconds) First results are also reported
and discussed.
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Title: Solar Magnetized Tornadoes: Rotational Motion in a Tornado-like
Prominence
Authors: Su, Yang; Gömöry, Peter; Veronig, Astrid; Temmer, Manuela;
Wang, Tongjiang; Vanninathan, Kamalam; Gan, Weiqun; Li, YouPing
2014ApJ...785L...2S Altcode: 2013arXiv1312.5226S
Su et al. proposed a new explanation for filament formation and
eruption, where filament barbs are rotating magnetic structures driven
by underlying vortices on the surface. Such structures have been noticed
as tornado-like prominences when they appear above the limb. They may
play a key role as the source of plasma and twist in filaments. However,
no observations have successfully distinguished rotational motion of
the magnetic structures in tornado-like prominences from other motions
such as oscillation and counter-streaming plasma flows. Here we report
evidence of rotational motions in a tornado-like prominence. The
spectroscopic observations in two coronal lines were obtained from a
specifically designed Hinode/EIS observing program. The data revealed
the existence of both cold and million-degree-hot plasma in the
prominence leg, supporting the so-called prominence-corona transition
region. The opposite velocities at the two sides of the prominence and
their persistent time evolution, together with the periodic motions
evident in SDO/AIA dark structures, indicate a rotational motion of
both cold and hot plasma with a speed of ~5 km s<SUP>-1</SUP>.
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Title: Inferring spectral characteristics of the Hα spectral line
observed by the DOT Lyot filter
Authors: Koza, J.; Rybák, J.; Gömöry, P.; Kučera, A.
2014CoSka..44...43K Altcode:
A tunable Lyot filter can serve as a spectroscopic device rendering
wide-field 2-D pseudospectroscopy of solar structures and follow-up
crude reconstruction of a spectral line profile at each pixel within the
field of view. We developed a method of inferring of the Doppler shift,
the core intensity, the core width, and the core asymmetry of the Hα
spectral line observed by the Lyot filter installed on the Dutch Open
Telescope (DOT). The spectral characteristics are inferred through the
fitting of five intensity samples, separated from each other by 0.35 Å,
by a 4<SUP>th</SUP>-order polynomial, a Gaussian, and a parabola. We
use the atlas Hα profile as a reference in estimating deviations
of the derived spectral characteristics. The Gaussian is the most
preferable means for measurements of the Doppler shift with deviations
smaller than 1 km s<SUP>-1</SUP>. When using the 4<SUP>th</SUP>-order
polynomial, deviations are within the interval ±2.5 km s<SUP>-1</SUP>,
but it renders comparable deviations of the core intensity and the
width as the Gaussian. The deviations are largely insensitive to the
shape of the filter transmission, but depend mostly non-linearly on
the Doppler shift. Therefore, they do not cancel out if the spectral
characteristics are represented by their relative variations. Results
can be used as corrections of spectral characteristics extracted from
area-averaged Hα profiles acquired by the DOT Lyot filter.
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Title: The association between sunspot magnetic fields and
superpenumbral fibrils
Authors: Louis, R. E.; Balthasar, H.; Kuckein, C.; Gömöry, P.;
Puschmann, K. G.; Denker, C.
2014AN....335..161L Altcode: 2013arXiv1312.1879L
Spectropolarimetric observations of a sunspot were carried out with
the Tenerife Infrared Polarimeter at Observatorio del Teide, Tenerife,
Spain. Maps of the physical parameters were obtained from an inversion
of the Stokes profiles observed in the infrared Fe I line at 15 648
Å. The regular sunspot consisted of a light bridge which separated the
two umbral cores of the same polarity. One of the arms of the light
bridge formed an extension of a penumbral filament which comprised
weak and highly inclined magnetic fields. In addition, the Stokes V
profiles in this filament had an opposite sign as the sunspot and some
resembled Stokes Q or U. This penumbral filament terminated abruptly
into another at the edge of the sunspot, where the latter was relatively
vertical by about 30<SUP>o</SUP>. Chromospheric H\alpha and He II 304
Åfiltergrams revealed three superpenumbral fibrils on the limb-side
of the sunspot, in which one fibril extended into the sunspot and was
oriented along the highly inclined penumbral counterpart of the light
bridge. An intense, elongated brightening was observed along this fibril
that was co-spatial with the intersecting penumbral filaments in the
photosphere. Our results suggest that the disruption in the sunspot
magnetic field at the location of the light bridge could be the source
of reconnection that led to the intense chromospheric brightening and
facilitated the supply of cool material in maintaining the overlying
superpenumbral fibrils.
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Title: Transmission profile of the Dutch Open Telescope Hα Lyot
filter
Authors: Koza, J.; Hammerschlag, R. H.; Rybák, J.; Gömöry, P.;
Kučera, A.; Schwartz, P.
2014AN....335..409K Altcode: 2017arXiv171209253K
Context Accurate knowledge of the spectral transmission profile of
a Lyot filter is important, in particular in comparing observations
with simulated data. The paper summarizes available facts about the
transmission profile of the Dutch Open Telescope (DOT) Hα Lyot filter
pointing to a discrepancy between sidelobe-free Gaussian-like profile
measured spectroscopically and signatures of possible leakage of
parasitic continuum light in DOT Hα images. We compute wing-to-center
intensity ratios resulting from convolutions of Gaussian and square
of the sinc function with the Hα atlas profile and compare them with
the ratios derived from observations of the quiet Sun chromosphere at
disk center. We interpret discrepancies between the anticipated and
observed ratios and the sharp limb visible in the DOT Hα image as an
indication of possible leakage of parasitic continuum light. A method
suggested here can be applied also to indirect testing of transmission
profiles of other Lyot filters. We suggest two theoretical transmission
profiles of the DOT Hα Lyot filter which should be considered as the
best available approximations. Conclusive answer can only be given by
spectroscopic re-measurement of the filter.
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Title: Coronal Multi-channel Polarimeter at the Lomnicky Peak
Observatory
Authors: Schwartz, P.; Ambroz, J.; Gömöry, P.; Kozák, M.; Kučera,
A.; Rybák, J.; Tomczyk, S.; Sewell, S.; Aumiller, P.; Summers, R.;
Sutherland, L.; Watt, A.
2014IAUS..300..521S Altcode:
Coronal Multi-channel Polarimeter (CoMP-S), developed by HAO/NCAR, has
been introduced to regular operation at the Lomnicky Peak Observatory
(High Tatras in northern Slovakia, 2633 m a.s.l.) of the Astronomical
Institute of Slovak Academy of Sciences. We present here the technical
parameters of the current version of the instrument and its potential
for observations of prominences in the visual and near-IR spectral
regions. The first results derived from observations of prominences
in the Hα emission line taken during a coordinated observing campaign
of several instruments in October 2012 are shown here.
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Title: Evidence of quiet-Sun chromospheric activity related to an
emerging small-scale magnetic loop
Authors: Gömöry, P.; Balthasar, H.; Puschmann, K. G.
2013A&A...556A...7G Altcode: 2013arXiv1306.3393G
<BR /> Aims: We investigate the temporal evolution of magnetic flux
emergence in the quiet-Sun atmosphere close to disk center. <BR />
Methods: We combined high-resolution SoHO/MDI magnetograms with TRACE
observations taken in the 1216 Å channel to analyze the temporal
evolution of an emerging small-scale magnetic loop and its traces
in the chromosphere. <BR /> Results: We find signatures of flux
emergence very close to the edge of a supergranular network boundary
located at disk center. The new emerging flux appeared first in the MDI
magnetograms in form of an asymmetric bipolar element, i.e., the patch
with negative polarity is roughly twice as weak as the corresponding
patch with opposite polarity. The average values of magnetic flux and
magnetic flux densities reached 1.6 × 10<SUP>18</SUP> Mx, - 8.5 ×
10<SUP>17</SUP> Mx, and 55 Mx cm<SUP>-2</SUP>, -30 Mx cm<SUP>-2</SUP>,
respectively. The spatial distance between the opposite polarity
patches of the emerged feature increased from about 2.″5 to 5.″0
during the lifetime of the loop, which was 36 min. A more precise
lifetime-estimate of the feature was not possible because of a gap
in the temporal sequence of the MDI magnetograms. The chromospheric
response to the emerged magnetic dipole occurred ~9 min later than in
the photospheric magnetograms. It consisted of a quasi-periodic sequence
of time-localized brightenings visible in the 1216 Å TRACE channel for
~14 min that were co-spatial with the axis connecting the two patches of
opposite magnetic polarity. <BR /> Conclusions: We identify the observed
event as a small-scale magnetic loop emerging at photospheric layers
that subsequently rose to the chromosphere. We discuss the possibility
that the fluctuations detected in the chromospheric emission probably
reflect magnetic-field oscillations which propagate to the chromosphere
in the form of waves.
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Title: Search for Alfvén waves in a bright network element observed
in Hα
Authors: Koza, J.; Sütterlin, P.; Gömöry, P.; Rybák, J.;
Kučera, A.
2013CoSka..43....5K Altcode: 2013arXiv1304.4027K
Alfvén waves are considered as potential transporters of energy
heating the solar corona. We seek spectroscopic signatures of the
Alfvén waves in the chromosphere occupied by a bright network element,
investigating temporal variations of the spectral width, intensity,
Dopplershift, and the asymmetry of the core of the Hα spectral
line observed by the tunable Lyot filter installed on the Dutch Open
Telescope. The spectral characteristics are derived through the fitting
of five intensity samples, separated from each other by 0.35 Å, by a
4<SUP>th</SUP>-order polynomial. The bright network element displays
the most pronounced variations of the Dopplershift varying from 0 to 4
km s<SUP>-1</SUP> about the average of 1.5 km s<SUP>-1</SUP>. This fact
implies a persistent redshift of the Hα core with a redward asymmetry
of about 0.5 km s<SUP>-1</SUP>, suggesting an inverse-C bisector. The
variations of the core intensity up to ±10 % and the core width up to
±5 % about the respective averages are much less pronounced, but still
detectable. The core intensity variations lag behind the Dopplershift
variations about 2.1 min. The Hα core width tends to correlate with
the Dopplershift and anticorrelate with the asymmetry, suggesting that
more redshifted Hα profiles are wider and the broadening of the Hα
core is accompanied with a change of the core asymmetry from redward
to blueward. We also found a striking anticorrelation between the
core asymmetry and the Dopplershift, suggesting a change of the core
asymmetry from redward to blueward with an increasing redshift of the
Hα core. The data and the applied analysis do not show meaningful
tracks of Alfvén waves in the selected network element.
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Title: Properties of a Decaying Sunspot
Authors: Balthasar, H.; Beck, C.; Gömöry, P.; Muglach, K.; Puschmann,
K. G.; Shimizu, T.; Verma, M.
2013CEAB...37..435B Altcode: 2013arXiv1301.1562B
A small decaying sunspot was observed with the Vacuum Tower Telescope
(VTT) on Tenerife and the Japanese Hinode satellite. We obtained
full Stokes scans in several wavelengths covering different heights
in the solar atmosphere. Imaging time series from Hinode and the
Solar Dynamics Observatory (SDO) complete our data sets. The spot is
surrounded by a moat flow, which persists also on that side of the
spot where the penumbra already had disappeared. Close to the spot,
we find a chromospheric location with downflows of more than 10 km
s^{-1} without photospheric counterpart. The height dependence of
the vertical component of the magnetic field strength is determined
in two different ways that yielded different results in previous
investigations. Such a difference still exists in our present data,
but it is not as pronounced as in the past.
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Title: A quiescent prominence observed in the Hα line by the COMP-S
instrument at the Lomnický Peak Observatory
Authors: Schwartz, P.; Rybák, J.; Kučera, A.; Kozák, M.; Ambróz,
J.; Gömöry, P.
2012CoSka..42..135S Altcode:
A prominence above the NEE limb was observed by the COMP-S instrument
attached to the ZEISS coronagraph located at the Lomnický Peak
Observatory. Observations were carried out on Nov 2, 2011 between
14:01:13 and 14:11:34 UT. The filter of the instrument was tuned during
measurements sequentially in five wavelengths within the profile of
the Hα line: 0, ±1, ±2 Å around 6563 Å. FWHM of the transmission
function of the filter was ∼0.4Å at these wavelengths. Data were
not absolutely calibrated, therefore they could be fitted using only a
simple cloud model (1D geometry, a complete frequency redistribution,
a source function independent of the optical depth) to diagnose the
prominence plasma. As five wavelength points in the profile were not
enough for an automatic fitting, five positions at the prominence were
chosen for the analysis. Observed data from the five positions were
simulated using the cloud model and groups of different models were
found for each position. It means that the wavelength scale of a step
as large as 1 Å when used for the Hα line is not fine enough for
estimation of a correct and unique model. Simulating observations
using three different finer wavelength scales it was found that
the wavelength scale with a step of 0.3 Å and even more finer in
the line core (step of 0.1 Å) is already suitable for more precise
and unambiguous plasma diagnostics. We also show that for correct
plasma diagnostics it is crucial to take into account an effect of a
finite width of the transmission function of the filter. If observed
data were fitted irrespectively of this important effect, an error
in estimated model parameters could exceed even 100 %, except for
the Doppler velocities, for which the error would be much smaller,
e.g. for velocities up to 20 km s<SUP>-1</SUP> the error is below 1 %.
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Title: Plasma Diagnostics of an EIT Wave Observed by Hinode/EIS
and SDO/AIA
Authors: Veronig, A. M.; Gömöry, P.; Kienreich, I. W.; Muhr, N.;
Vršnak, B.; Temmer, M.; Warren, H. P.
2011ApJ...743L..10V Altcode: 2011arXiv1111.3505V
We present plasma diagnostics of an Extreme-Ultraviolet
Imaging Telescope (EIT) wave observed with high cadence in
Hinode/Extreme-Ultraviolet Imaging Spectrometer (EIS) sit-and-stare
spectroscopy and Solar Dynamics Observatory/Atmospheric Imaging
Assembly imagery obtained during the HOP-180 observing campaign on 2011
February 16. At the propagating EIT wave front, we observe downward
plasma flows in the EIS Fe XII, Fe XIII, and Fe XVI spectral lines
(log T ≈ 6.1-6.4) with line-of-sight (LOS) velocities up to 20
km s<SUP>-1</SUP>. These redshifts are followed by blueshifts with
upward velocities up to -5 km s<SUP>-1</SUP> indicating relaxation
of the plasma behind the wave front. During the wave evolution, the
downward velocity pulse steepens from a few km s<SUP>-1</SUP> up to 20
km s<SUP>-1</SUP> and subsequently decays, correlated with the relative
changes of the line intensities. The expected increase of the plasma
densities at the EIT wave front estimated from the observed intensity
increase lies within the noise level of our density diagnostics from
EIS Fe XIII 202/203 Å line ratios. No significant LOS plasma motions
are observed in the He II line, suggesting that the wave pulse was not
strong enough to perturb the underlying chromosphere. This is consistent
with the finding that no Hα Moreton wave was associated with the
event. The EIT wave propagating along the EIS slit reveals a strong
deceleration of a ≈ -540 m s<SUP>-2</SUP> and a start velocity of v
<SUB>0</SUB> ≈ 590 km s<SUP>-1</SUP>. These findings are consistent
with the passage of a coronal fast-mode MHD wave, pushing the plasma
downward and compressing it at the coronal base.
---------------------------------------------------------
Title: The LSO/KSO Hα prominence catalogue: cross-calibration of data
Authors: Rybák, J.; Gömöry, P.; Mačura, R.; Kučera, A.; Rušin,
V.; Pötzi, W.; Baumgartner, D.; Hanslmeier, A.; Veronig, A.;
Temmer, M.
2011CoSka..41..133R Altcode:
We present work on the extension of the homogeneous prominence
catalogue created for the epoch 1967 — 2009 at the Lomnicky Peak
Observatory (LSO) by incorporating new data acquired at the Kanzelhöhe
Observatory for Solar and Environmental Research (KSO). We use data of
20 Hα prominences observed almost simultaneously at both observatories
during four days in August/September 2009 to analyze the significance
of differences of the determined parameters used in the Hα prominence
catalogue. A reduction of the data from KSO and adaptation of the
resulting parameters to fit the parameters of the LSO catalogue confirm
that no special homogenization is needed to create a common catalogue
data set. Thus, we justified that the LSO catalogue could be extended
onward in the future using a more comprehensive database of observations
from KSO.
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Title: Spectroscopic Observations of a Coronal Moreton Wave
Authors: Harra, Louise K.; Sterling, Alphonse C.; Gömöry, Peter;
Veronig, Astrid
2011ApJ...737L...4H Altcode:
We observed a coronal wave (EIT wave) on 2011 February 16, using
EUV imaging data from the Solar Dynamics Observatory/Atmospheric
Imaging Assembly (AIA) and EUV spectral data from the Hinode/EUV
Imaging Spectrometer (EIS). The wave accompanied an M1.6 flare that
produced a surge and a coronal mass ejection (CME). EIS data of the
wave show a prominent redshifted signature indicating line-of-sight
velocities of ~20 km s<SUP>-1</SUP> or greater. Following the main
redshifted wave front, there is a low-velocity period (and perhaps
slightly blueshifted), followed by a second redshift somewhat weaker
than the first; this progression may be due to oscillations of the EUV
atmosphere set in motion by the initial wave front, although alternative
explanations may be possible. Along the direction of the EIS slit the
wave front's velocity was ~500 km s<SUP>-1</SUP>, consistent with
its apparent propagation velocity projected against the solar disk
as measured in the AIA images, and the second redshifted feature had
propagation velocities between ~200 and 500 km s<SUP>-1</SUP>. These
findings are consistent with the observed wave being generated by the
outgoing CME, as in the scenario for the classic Moreton wave. This
type of detailed spectral study of coronal waves has hitherto been a
challenge, but is now possible due to the availability of concurrent
AIA and EIS data.
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Title: Heating of the quiet solar corona from measurements of the
FET/TESIS instrument on-board the KORONAS-FOTON satellite
Authors: Rybák, J.; Gömöry, P.; Benz, A.; Bogachev, P.; Brajša, R.
2010nspm.conf..107R Altcode:
The paper presents the first results of the observations of time
evolution of the quiet solar corona brightenings obtained due to
very rapid photography of the corona with full-disk EUV telescopes
of the FET/TESIS instrument onboard the KORONA FOTON satellite. The
measurements were performed simultaneously in the emission of the Fe
IX / X 17.1 and Fe VIII 13.1 spectral lines with 10 second temporal
cadence and spatial scale of 1.7 arc seconds within one hour. This
test observation, carried out on 15 July 2009, was analyzed in order
to determine whether this type of observation can be used to identify
individual microevents in the solar corona heating that are above the
tresholds of spatial and temporal resolutions of the observations
of non-active regions in the solar atmosphere. For this purpose,
a simple method was used involving cross-correlation of the plasma
emission time evolution at different temperatures, each time from
observations of identical elements. The results obtained are confronted
with the expected observable manifestations of the corona heating
via nanoflares. TESIS is a set of instruments for the Sun photography
developed in the Lebedev Physics Institute of the Russian Academy of
Sciences that was launched into orbit in January 2009.
---------------------------------------------------------
Title: Koronálny multikanálový polarimeter pre observatórium
Lomnický štít
---------------------------------------------------------
Title: Koronálny multikanálový polarimeter
pre observatórium Lomnický štít
---------------------------------------------------------
Title: Coronal multichannel
polarimeter for Lomnický štít Observatory.
Authors: Rybák, J.; Ambróz, J.; Gömöry, P.; Kozák, M.; Kučera,
A.; Tomczyk, S.; Sewell, S.; Summers, R.; Sutherland, L.; Watt, A.
2010nspm.conf..196R Altcode:
The contribution presents the process of development and preparation
of the Coronal Multi-channel Polarimeter (COMP-S) for the Lomnický
štít Observatory of the SAS Astronomy Institute. The design of the
device is based on the experience gained in recent years with the CoMP
(High Altitude Observatory / NCAR; Boulder, USA) instrument. The device
will be a combination of two main optical components: the Lyot tunable
filter and polarimeter, and is prepared specifically for one of the
20 cm Zeiss coronagraph at the Lomnický štít Observatory where it
will be installed in 2011. CoMP-S will differ from its predecessor
in several respects. The most important difference is that CoMP-S
will be able to observe the corona and chromospheric emission lines
in the wavelength range from 530 to 1083 nm. This feature will be
achieved using superachromatic wave plates and dichroic polarizers
with wide bandwidth. Furthermore, in the CoMP-S instrument new SWIFT
liquid crystals of Meadowlark Optics company will be used as variable
retarders instead of nematic liquid crystal retarders (LCVR) which
will considerably shorten the measuring process. Ferroelectric liquid
crystals will provide measurements of the full Stokes vector with nearly
optimal polarization throughout the whole instrument bandwidth. Recently
developed sCMOS cameras are to provide diffraction limit resolution of
observations, with the 860x680 arc second field and 30-frames-per-second
cadence. The device will be used in the Astronomical Observatory of SAS
at Lomnický štít primarily for spectrum polarimetry of prominences
and coronal loops of the active solar regions.
---------------------------------------------------------
Title: Slnečná aktivita a kozmické 'iarenie: magnetické pole
Slnka a úroveň kozmického žiarenia
---------------------------------------------------------
Title: Slnečná aktivita a
kozmické 'iarenie: magnetické pole Slnka a úroveň kozmického
žiarenia
---------------------------------------------------------
Title: Solar activity and cosmic radiation: Sun's magnetic
field and cosmic radiation levels.
Authors: Bodnárová, M.; Rybák, J.; Gömöry, P.; Kudela, K.
2010nspm.conf..175B Altcode:
In this work we have analyzed the correlation of the Sun's magnetic
activity and cosmic radiation levels during the period 1951-2004. As a
solar magnetic activity indicator, affecting the cosmic radiation, we
have chosen open magnetic field configurations which we characterized
by an open magnetic flux factor (OMFF). The OMFF was calculated from
the intensity measurements of the green coronal line. In calculations
leading to the relation between the OMFF and galactic cosmic radiation
(GCR) levels the cross-correlation of these datasets was used. The goal
of this contribution was to find mainly time-dependent changes in the
evolution of the OMFF and GCR correlation. In order to do so,besides
the correlation calculations based on the long time series of the
OMFF and GCR data covering the entire period 1951-2004 we have also
calculated the correlation of the OMFF and GCR data from shorter periods
(180 days). We have found that the cross-correlation evolution varies
depending on the phase of the solar cycle. During the minimum the
evolution is characterized by conspicuous periodicity with a period
~ 14 days and the cross-correlation function takes statistically
significant values. During the maximum the period of the variations
is not clear and the cross-correlation function takes low values that
are not statistically significant.
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Title: Multiwavelength Imaging and Spectroscopy of Chromospheric
Evaporation in an M-class Solar Flare
Authors: Veronig, A. M.; Rybák, J.; Gömöry, P.; Berkebile-Stoiser,
S.; Temmer, M.; Otruba, W.; Vršnak, B.; Pötzi, W.; Baumgartner, D.
2010ApJ...719..655V Altcode: 2010arXiv1007.0930V
We study spectroscopic observations of chromospheric evaporation mass
flows in comparison with the energy input by electron beams derived
from hard X-ray (HXR) data for the white-light M2.5 flare of 2006 July
6. The event was captured in high-cadence spectroscopic observing mode
by SOHO/CDS combined with high-cadence imaging at various wavelengths
in the visible, extreme ultraviolet, and X-ray domain during the joint
observing campaign JOP171. During the flare peak, we observe downflows
in the He I and O V lines formed in the chromosphere and transition
region, respectively, and simultaneous upflows in the hot coronal
Si XII line. The energy deposition rate by electron beams derived
from RHESSI HXR observations is suggestive of explosive chromospheric
evaporation, consistent with the observed plasma motions. However, for
a later distinct X-ray burst, where the site of the strongest energy
deposition is exactly located on the Coronal Diagnostics Spectrometer
(CDS) slit, the situation is intriguing. The O V transition region
line spectra show the evolution of double components, indicative of
the superposition of a stationary plasma volume and upflowing plasma
elements with high velocities (up to 280 km s<SUP>-1</SUP>) in single
CDS pixels on the flare ribbon. However, the energy input by electrons
during this period is too small to drive explosive chromospheric
evaporation. These unexpected findings indicate that the flaring
transition region is much more dynamic, complex, and fine structured
than is captured in single-loop hydrodynamic simulations.
---------------------------------------------------------
Title: Magnetic loop emergence within a granule
Authors: Gömöry, P.; Beck, C.; Balthasar, H.; Rybák, J.; Kučera,
A.; Koza, J.; Wöhl, H.
2010A&A...511A..14G Altcode: 2009arXiv0910.4449G
<BR /> Aims: We investigate the temporal evolution of magnetic
flux emerging within a granule in the quiet-Sun internetwork at
disk center. <BR /> Methods: We combined IR spectropolarimetry of
high angular resolution performed in two Fe i lines at 1565 nm with
speckle-reconstructed G-band imaging. We determined the magnetic
field parameters by a LTE inversion of the full Stokes vector using
the SIR code, and followed their evolution in time. To interpret
the observations, we created a geometrical model of a rising loop in
3D. The relevant parameters of the loop were matched to the observations
where possible. We then synthesized spectra from the 3D model for a
comparison to the observations. <BR /> Results: We found signatures of
magnetic flux emergence within a growing granule. In the early phases,
a horizontal magnetic field with a distinct linear polarization signal
dominated the emerging flux. Later on, two patches of opposite circular
polarization signal appeared symmetrically on either side of the linear
polarization patch, indicating a small loop-like structure. The mean
magnetic flux density of this loop was roughly 450 G, with a total
magnetic flux of around 3 × 10<SUP>17</SUP> Mx. During the ~12 min
episode of loop occurrence, the spatial extent of the loop increased
from about 1 to 2 arcsec. The middle part of the appearing feature
was blueshifted during its occurrence, supporting the scenario of an
emerging loop. There is also clear evidence for the interaction of
one loop footpoint with a preexisting magnetic structure of opposite
polarity. The temporal evolution of the observed spectra is reproduced
to first order by the spectra derived from the geometrical model. During
the phase of clearest visibility of the loop in the observations,
the observed and synthetic spectra match quantitatively. <BR />
Conclusions: The observed event can be explained as a case of flux
emergence in the shape of a small-scale loop. The fast disappearance
of the loop at the end could possibly be due to magnetic reconnection.
---------------------------------------------------------
Title: Multi-wavelength fine structure and mass flows in solar
microflares
Authors: Berkebile-Stoiser, S.; Gömöry, P.; Veronig, A. M.; Rybák,
J.; Sütterlin, P.
2009A&A...505..811B Altcode:
Aims: We study the multi-wavelength characteristics at high spatial
resolution, as well as chromospheric evaporation signatures of solar
microflares. To this end, we analyze the fine structure and mass
flow dynamics in the chromosphere, transition region and corona of
three homologous microflares (GOES class <A9/0.7 with/without
background), which occurred on July 4, 2006 in AR 10898. <BR
/>Methods: A multi-wavelength analysis using temporally and spatially
highly resolved imaging data from the Dutch open telescope (Hα,
Ca ii H), the transition region and coronal explorer (17.1 nm),
the extreme-ultraviolet imaging telescope (19.5 nm), and the Reuven
Ramaty high energy solar spectroscopic imager (≳3 keV) was carried
out. EUV line spectra provided by the coronal diagnostic spectrometer
are searched for Doppler shifts in order to study associated
plasma flows at chromospheric (He i, T∼3.9× 10<SUP>4</SUP> K),
transition region (e.g. O v, T∼ 2.6× 10<SUP>5</SUP> K), and
coronal temperatures (Si xii, T∼ 2× 10<SUP>6</SUP> K). RHESSI
X-ray spectra provide information about non-thermal electrons. <BR
/>Results: The multi-wavelength appearance of the microflares is in
basic agreement with the characteristics of large flares. For the
first event, a complex flare sequence is observed in TRACE 17.1 nm
images (T≈ 1 MK), which show several brightenings, narrow loops
of enhanced emission, and an EUV jet. EIT 19.5 nm data (T≈ 1.5 MK)
exhibit similar features for the third event. DOT measurements show
finely structured chromospheric flare brightenings for all three events,
loop-shaped fibrils of increased emission between Hα brightenings, as
well as a similar feature in Ca ii. For all three events, a RHESSI X-ray
source (3-8 keV, T ≳ 10 MK) is located in between two chromospheric
brightenings situated in magnetic flux of opposite polarity. We find
the flow dynamics associated with the events to be very complex. In
the chromosphere and transition region, CDS observed downflows for
the first (v ≲ 40 km s<SUP>-1</SUP>), and upflows for the second
event (v ≲ 40 km s<SUP>-1</SUP>). During the third microflare, we
find upflows of ≲ 20 km s<SUP>-1</SUP> and also weak downflows of
≲20 km s<SUP>-1</SUP> in two separate brightenings. For all three
microflares, multi-component fitting is needed for several profiles
of He i, O v, and Ne vi lines observed at the flare peaks, which
indicate spatially unresolved, oppositely directed flows of ≲180
km s<SUP>-1</SUP>. We interpret these flows as twisting motions of
the flare loops. Loop-shaped fibrils in between Hα brightenings
showing opposite flow directions (v≈5 km s<SUP>-1</SUP>) are also
observed in DOT Hα Dopplergrams. RHESSI X-ray spectra show evidence
of non-thermal bremsstrahlung for two of the three microflares. The
electron beam flux density deposited in the chromosphere for these
events is estimated to straddle the threshold heating flux between
gentle and explosive evaporation. <P />Appendix A and the movie are
only available in electronic form at http://www.aanda.org
---------------------------------------------------------
Title: The three-dimensional structure of the magnetic field of
a sunspot
Authors: Balthasar, Horst; Gömöry, Peter
2009IAUS..259..225B Altcode:
Spectro-polarimetric observations in several spectral lines allow
to determine the height variation of the magnetic field of a small
sunspot throughout the solar photosphere. The full Stokes-vector is
measured with high spatial resolution. From these data we derive the
magnetic field vector. The magnetic field strength decreases with
height everywhere in the spot, even in the outer penumbra where some
other authors have reported the opposite. The precise value of this
decrease depends on the exact position in the spot. Values vary between
0.5 and 2.2 G km<SUP>-1</SUP> when they are determined from an iron
and a silicon line in the near infrared. The magnetic field is less
inclined in the higher layers where the silicon line is formed. Once
the magnetic vector field is known, it is straight forward to determine
current densities and helicities. Current densities exhibit a radial
structure in the penumbra, although it is still difficult to correlate
this with the structure seen in the intensity continuum. In spite of
this, current densities have a potential to serve as diagnostic tools
to understand the penumbra, at least with the spatial resolution of
the upcoming telescopes. The mean infered helicity is negative, as
expected for a spot in the northern hemisphere. Nevertheless, there
are locations inside the spot with positive helicity.
---------------------------------------------------------
Title: Observations of Chromospheric Evaporation Flows in RHESSI
Microflares
Authors: Berkebile-Stoiser, S.; Gömöry, P.; Veronig, A.; Rybák, J.
2009CEAB...33..169B Altcode:
We present the analysis of two homologous microflares of GOES class
A9 with respect to mass flows in the chromosphere and transition
region. Both events show non-thermal emission (evidence for beamed
electrons) in RHESSI X-ray spectra. As outlined by observations of
the Coronal Diagnostic Spectrometer, we find for the first event
downflows in the He I, O V and Ne VI line reaching speeds up to 40
km s^{-1} at the position of chromospheric flare brightenings. On
the other hand, upflows with velocities ≲40 km^{-1} are observed
for the second microflare. <P />According to hydrodynamic flare
simulations, the non-thermal electron energy density F deposited in
the chromosphere determines if chromospheric evaporation is `gentle' or
`explosive'. Thus, we derive rough estimates for F in our microflares
and compare the results to the observed CDS flow properties.
---------------------------------------------------------
Title: Multi-wavelength Observations of Microflares Near an Active
Region
Authors: Bein, B.; Veronig, A.; Rybak, J.; Gömöry, P.;
Berkebile-Stoiser, S.; Sütterlin, P.
2009CEAB...33..179B Altcode:
We study the multi-wavelength characteristics of a microflaring active
region (AR 10898) near disc centre. The analysed data were from the
4^{th} of July 2006, and were recorded by DOT (Hα, Ca II H), RHESSI
(X-rays), TRACE (EUV) and SOHO/MDI (magnetograms). The identified
microflare events were studied with respect to their magnetic field
configuration and their multi-wavelength time evolution.
---------------------------------------------------------
Title: Solar Convection and Oscillation Interaction
Authors: Hanslmeier, A.; Kučera, A.; Rybák, J.; Wöhl, H.;
Gömöry, P.
2009CEAB...33...51H Altcode:
In this paper we investigate bisectors of solar photospheric lines. The
bisectors reflect vertical velocity gradients over the height of line
formation and therefore reveal important information about the dynamics
in these layers. Their shape and shift is influenced by (a) convective
motions, (b) oscillatory motions that can act differently at different
photospheric heights. The bisectors are selected from different
locations that show mainly a granular evolution or an intergranular
evolution. Two selection criteria were applied: continuum intensity
(enhanced for granular bisectors, reduced for intergranular bisectors),
and full width at half maximum values (enhanced for intergranular
bisectors). The results demonstrate how oscillatory motions influence
the bisectors as a whole. In the example given a smaller amplitude of
oscillations over intergranular areas is indicated.
---------------------------------------------------------
Title: The three-dimensional structure of sunspots. I. The height
dependence of the magnetic field
Authors: Balthasar, H.; Gömöry, P.
2008A&A...488.1085B Altcode:
Aims: We investigate the height dependence of the magnetic field
of a sunspot, which has been until now a controversial issue. <BR
/>Methods: Full-Stokes profiles of a sunspot, derived from infrared
spectro-polarimetric measurements, were investigated. The magnetic
field strength, inclination and azimuth were obtained using an inversion
code. The results from two different spectral lines deliver the height
dependence of the magnetic vector field. Vertical current densities
and helicities as well as the vertical derivative of the vertical
component of the magnetic field strength are calculated using Maxwell's
equations. <BR />Results: Inside the spot, the total magnetic field
strength decreases with height, even in the outer penumbra, where
the opposite trend was reported by other investigators. Outside the
spot, the field strength increases with height apart from at a few
small locations. This result is interpreted in terms of magnetic
canopies. Magnetic field lines are less inclined in higher layers
everywhere in the field of view. In the umbra, the vertical component
of the magnetic field decreases by values in the range 0.5-2.2
G km<SUP>-1</SUP>, depending on the applied method. Mean values
in the inner penumbra are smaller than in the umbra. In the outer
penumbra, the vertical magnetic component increases independently of
the local intensity distribution. A pore close to the spot exhibits
a more rapid decrease with height than the spot itself. The electric
current densities and helicities depend on the fine structure of the
sunspots. Typical values of the current densities vary in the range
±40 mA m<SUP>-2</SUP>. The mean values are -11 mA m<SUP>-1</SUP> for
the umbra and -2 mA m<SUP>-1</SUP> for the penumbra, respectively, but
the propagated errors are of the same order as the mean values. There
are indications that the radial structure of the penumbra is related
to enhanced current densities, but at the present resolution we are
unable to establish a correlation with local intensity fluctuations. <BR
/>Conclusions: If the spatial resolution is sufficiently high, electric
current densities and helicities could be applied as reliable diagnostic
tools for understanding penumbral fine structure.
---------------------------------------------------------
Title: Multi-wavelength Observations of Dynamic Fibrils in the Upper
Photosphere and Chromosphere
Authors: Kucera, A.; Beck, Ch.; Gomory, P.; Koza, J.; Woehl, H.;
Rybak, J.
2008ESPM...12.2.52K Altcode:
Spatial and temporal evolution of dynamic fibrils (DF) as well as
coupling with photospheric features was investigated. <P />The
main target were remnants in the active region 10997 on May 28,
2008. We used about 1 hour series of multi wavelength simultaneous
observations of the DFs and corresponding photospheric features. The
observations were performed with the german Vacuum Tower Telescope
equipped with several post-focus instruments. Namely: TESOS (Triple
Etalon SOlar Spectrometer) instrument was used in polarimetric mode
(VIP=Visual Imaging Polarimeter) to register 2D spectra of the DFs in
H-alpha line and in magnetically sensitive Fe I 630.2 nm line. TIP
(Tenerife Infrared Polarimeter) mounted on the Echelle spectrograph
was used for spectropolarimetric observations of two neutral iron
lines at 1.56 micrometers. We scanned 2D area 80" x 5", producing
thus 2D maps of intensity, velocity and magnetic field of the low
photosphere under the chromospheric fibril field. <P />Additionally
G-band and H-alpha images were registered with high cadence and
the supporting data from the TRACE satellite (17.1 nm, WL, Lyman
alpha line and 160 nm continuum) are also available. After careful
spatial coalignment of 2D maps we first selected numerous DFs in the
H-alpha images. Then we investigated temporal evolution of those DFs
concerning changes of their dimensions, positions and fluctuations
and correlated these characteristics with temporal evolution of the
intensities, velocities and magnetic field characteristics observed in
the spatially corresponding photosphere. The poster demonstrates the
complex observations, data reduction and coalignment and preliminary
results on coupling between DFs and underlying photospheric features.
---------------------------------------------------------
Title: Acceleration in Fast Halo CMEs and Synchronized Flare HXR
Bursts
Authors: Temmer, M.; Veronig, A. M.; Vršnak, B.; Rybák, J.; Gömöry,
P.; Stoiser, S.; Maričić, D.
2008ApJ...673L..95T Altcode:
We study two well-observed, fast halo CMEs, covering the full CME
kinematics including the initiation and impulsive acceleration phase,
and their associated flares. We find a close synchronization between the
CME acceleration profile and the flare energy release as indicated by
the RHESSI hard X-ray flux onsets, as well as peaks occur simultaneously
within 5 minutes. These findings indicate a close physical connection
between both phenomena and are interpreted in terms of a feedback
relationship between the CME dynamics and the reconnection process in
the current sheet beneath the CME.
---------------------------------------------------------
Title: Propagating Waves in the Chromospheric Network
Authors: Gömöry, P.; Rybák, J.; Kučera, A.; Curdt, W.; Wöhl, H.
2007ASPC..368..133G Altcode:
Wave modulation of ultraviolet emissions originated in and above quiet
chromospheric network is studied. In particular, cross-correlation,
wavelet analysis and phase difference analysis of the intensities
as well as the Doppler shifts of emission lines of He I 584.33 Å
(chromosphere), O V 629.73 Å (transition region) and Mg IX 368.07 Å
(corona) are employed to study waves at different heights and their
direction of propagation. The results are interpreted as evidence of
compressive waves that propagate downward from the transition region
to the chromosphere in the observed chromospheric network. Different
scenarios regarding the origin and source localization of these waves
are discussed.
---------------------------------------------------------
Title: Magnetic vector field above a sunspot
Authors: Gömöry, P.; Balthasar, H.
2007msfa.conf..221G Altcode:
We present an analysis of the spectro-polarimetricmeasurements of the
active region NOAA 10886 taken with the Tenerife Infrared Polarimeter
in the Fe I 10783 Å spectral line. The magnetic field strength and
the magnetic inclination and azimuth were inferred from the data
using the inversion code SIR. The vertical current densities and
the vertical derivative of the vertical component of the magnetic
field were then calculated for the leading spot of the AR 10886. We
revealed that typical values of the vertical current densities vary in
the range ± 40mAm-2 inside the spot. Moreover, we found an extended
area of enhanced vertical current densities in the umbra (values up
to -80mAm-2). Our analysis also showed that the vertical component
of the magnetic field strength decreases by 0.6 - 1.6Gkm-1 and 0.5 -
0.8Gkm-1 in the umbra and inner penumbra; on the other hand we found
an increase of the vertical component of the magnetic field in the
outer penumbra (typical values varying between 0.1 - 0.5Gkm-1).
---------------------------------------------------------
Title: Multi-Wavelength Observations with High Resolution of a M5.4
Flare from Ground and Space
Authors: Kucera, A.; Wöhl, H.; Rybák, J.; Gömöry, P.; Veronig, A.
2006ESASP.617E..68K Altcode: 2006soho...17E..68K
No abstract at ADS
---------------------------------------------------------
Title: SOHO/CDS observations of waves above the network
Authors: Gömöry, P.; Rybák, J.; Kučera, A.; Curdt, W.; Wöhl, H.
2006A&A...448.1169G Altcode:
We analyze temporal variations in the intensities and the Doppler shifts
of He i 584.33 Å (chromosphere), O v 629.73 Å (transition region),
and Mg ix 368.07 Å (corona) measured in and above chromospheric
network near disk center with the Coronal Diagnostic Spectrometer
(CDS) onboard the Solar and Heliospheric Observatory (SOHO). There is
significant correlation between the He i and O v modulations, with O v
intensity leading He i intensity by 27.3 s ± 4.6 s but no significant
time shift in the Doppler shift. Cross-correlation between the O v
and Mg ix intensities reveals multiple maxima without correlation
between their Doppler shifts. Wavelet power analysis gives evidence
of intermittent chromospheric and transition-region oscillations with
periodicities in the 250-450 s range and of coronal oscillations in
the 110-300 s range. Wavelet phase difference analysis shows that
the determined time shift between variations of the He i and O v
intensities is dominated by waves with about 300 s periodicity. We
interpret these results as giving evidence of compressive waves that
propagate downward from the transition region to the chromosphere in
the particular chromospheric network. We discuss different scenarios
regarding origin and source localization of waves, and we speculate
on their role in coronal heating above chromospheric network.
---------------------------------------------------------
Title: Analysis of Dynamics of Loops in AN Active Region Associated
with a Small C-Class Flare
Authors: Gömöry, P.; Rybák, J.; Kucera, A.; Wöhl, H.
2005ESASP.596E..56G Altcode: 2005ccmf.confE..56G
No abstract at ADS
---------------------------------------------------------
Title: Analysis of Doppler Shifts of Spectral Lines Obtained by the
CDS/SOHO Instrument
Authors: Gömöry, P.; Rybák, J.; Kučera, A.; Curdt, W.; Wöhl, H.
2005ASSL..320..203G Altcode: 2005smp..conf..203G
No abstract at ADS
---------------------------------------------------------
Title: Variability and Dynamics of the Outer Atmospheric Layers in
the Quiet Solar Network
Authors: Gömöry, P.; Rybák, J.; Kučera, A.; Curdt, W.; Wöhl, H.
2005HvaOB..29...71G Altcode:
A detailed study of the temporal evolution of the chromospheric He
I 584.33 Å and the transition region O V 629.73 Å emission line
intensities of quiet supergranular network of the Sun near disk centre
observed with Coronal Diagnostic Spectrometer (CDS) is presented. A
wavelet analysis of the 1729 s (28.8 min) long temporal series was
performed in order to derive the duration as well as periods of the
chromospheric and the transition region oscillations. The He I line
intensities show significant power for periods around 300 s (3.3 mHz),
which is relevant only in the second half of the observing sequence
(between 800 -- 1700 s). The temporal evolution corresponding to the
O V line intensities shows strong power around the period of 400 s
(2.5 mHz), which is significant during the whole observing sequence
as well as the oscillation of lower power for periods of around 250 s
(4.0 mHz), which is present only in the middle of the observing sequence
(between 700 -- 1300 s).
---------------------------------------------------------
Title: High Resolution Observations of a M5.4 Flare
Authors: Kučera, A.; Wöhl, H.; Rybák, J.; Gömöry, P.; Tomasz, F.
2005HvaOB..29..177K Altcode:
Hα observations of a M5.4 flare taken in the active region NOAA 10646
with the Vacuum Tower Telescope at Observatório del Teide, Tenerife,
on July 13, 2004 are presented. The temporal evolution of the area
of the flare and its morphological changes are investigated and
discussed. Simultaneous observations of the flare in EUV lines taken
with CDS/SOHO instrument are shown and additional data from GOES-10
instrument are compared.
---------------------------------------------------------
Title: Dynamics of the Quiet Upper Solar Atmosphere in the Network
Authors: Gömöry, P.; Rybák, J.; Kucera, A.; Curdt, W.; Wöhl, H.
2004ESASP.575..400G Altcode: 2004soho...15..400G
No abstract at ADS
---------------------------------------------------------
Title: On Mutual Relation Among the Outer Atmospheric Layers in
Network: SOHO/CDS Study
Authors: Gömöry, P.; Rybák, J.; Kucera, A.; Curdt, W.; Wöhl, H.
2004ESASP.547..303G Altcode: 2004soho...13..303G
SOHO/CDS measurements of emission in the network of the quiet solar
atmosphere near disk center were used to derive mutual relations
of emission and dynamics in different temperature regimes in/above
supergranular network. Cross-correlation functions of the line
intensities and the Doppler shifts of the chromospheric line He I 584.3
Å, the transition region line O V 629.7 Å and the coronal line Mg
IX 396.1 Å were calculated in order to study relative variability
of different atmospheric layers. Relatively high correlations were
found between the intensities and the Doppler shifts of the He I and
O V lines with two peaks of the intensity correlation function. The
maximum value of the correlation of intensities (CC = 0.86) was reached
for the zero time lag and the second maximum (CC = 0.78) was obtained
for the time lag -190s (O V precedes He I). Only one sharp peak (CC =
0.55) was detected in the Doppler shift correlation function of these
lines for the zero time lag. For the correlation of O V and Mg IX
intensities one peak (CC = 0.57) of the correlation function was also
discovered for the time lag +150s (Mg IX falls behind O V). In contrast,
no correlation was obtained for the Doppler shifts of the O V and Mg
IX lines. Summarizing we can assume clear relation in energy transfer
and/or mass motion between chromosphere and transition region but no
relation was found between corona and the lower parts of the solar
atmosphere above the particular network under study.
---------------------------------------------------------
Title: Transition region eruptive event observed with SOHO/CDS in
the quiet Sun network
Authors: Gömöry, P.; Rybák, J.; Kučera, A.; Curdt, W.; Wöhl, H.
2003HvaOB..27...67G Altcode:
CDS observations of the quiet Sun network in the chromospheric He I
584.33 Å and transition region O V 629.73 Å emission lines over
a time period of ∼ 29 min are presented. One eruptive event was
detected in this time series of data. The parameters of the network
eruptive event are derived and the type of this small-scale activity
is identified. The lifetime of the event was ∼ 1 min and it was
found only in the transition region emission line. This event had no
chromospheric counterpart. All O V spectral profiles of the eruptive
event were blueshifted and the maximal Doppler shift was -14.7 km
s<SUP>-1</SUP>. During an initial phase of the eruptive event, the
O V intensity enhancement factor was 2.3. These parameters indicate
that the observed event could be a transition region explosive event
but measured with the limited resolution of the CDS instrument.
