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Author name code: robustini
ADS astronomy entries on 2022-09-14
author:"Robustini, Carolina"
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Title: COCOPLOT: COlor COllapsed PLOTting software Using colour to
view 3D data as a 2D image
Authors: Druett, Malcolm K.; Pietrow, Alexander G. M.; Vissers,
Gregal J. M.; Robustini, Carolina; Calvo, Flavio
2022RASTI...1...29D Altcode: 2021arXiv211110786D
Most modern solar observatories deliver data products formatted as 3D
spatio-temporal data cubes, that contain additional, higher dimensions
with spectral and/or polarimetric information. This multi-dimensional
complexity presents a major challenge when browsing for features of
interest in several dimensions simultaneously. We developed the COlor
COllapsed PLOTting (COCOPLOT) software as a quick-look and context image
software, to convey spectral profile or time evolution from all the
spatial pixels ($x,y$) in a 3D [$n_x,n_y,n_\lambda$] or [$n_x,n_y,n_t$]
data cube as a single image, using color. This can avoid the need to
scan through many wavelengths, creating difference and composite images
when searching for signals satisfying multiple criteria. Filters are
generated for the red, green, and blue channels by selecting values
of interest to highlight in each channel, and their weightings. These
filters are combined with the data cube over the third dimension axis
to produce an $n_x \times n_y \times 3$ cube displayed as one true
color image. Some use cases are presented for data from the Swedish 1-m
Solar Telescope (SST) and IRIS, including H$\alpha$ solar flare data,
a comparison with $k$-means clustering for identifying asymmetries
in the Ca II K line and off-limb coronal rain in IRIS C II slit-jaw
images. These illustrate identification by color alone using COCOPLOT
of locations including line wing or central enhancement, broadening,
wing absorption, and sites with intermittent flows or time-persistent
features. COCOPLOT is publicly available in both IDL and Python.
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Title: COCOPLOT: COlor COllapsed PLOTting software
Authors: Druett, Malcolm K.; Pietrow, Alexander G. M.; Vissers,
Gregal J. M.; Robustini, Carolina
2021ascl.soft11008D Altcode:
The COCOPLOT (COlor COllapsed PLOTting) quick-look and context image
code conveys spectral profile information from all of the spatial
pixels in a 3D datacube as a single image using color. It can also
identify and expose temporal behavior and display and highlight
solar features. COCOPLOT thus aids in identifying regions of interest
quickly. The software is available in Python and IDL, and can be used
as a standalone package or integrated into other software.
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Title: Three-dimensional magnetic field structure of a flux-emerging
region in the solar atmosphere
Authors: Yadav, Rahul; de la Cruz Rodríguez, Jaime; Díaz Baso,
Carlos José; Prasad, Avijeet; Libbrecht, Tine; Robustini, Carolina;
Asensio Ramos, Andrés
2019A&A...632A.112Y Altcode: 2019arXiv191013279Y
We analyze high-resolution spectropolarimetric observations of a
flux-emerging region (FER) in order to understand its magnetic and
kinematic structure. Our spectropolarimetric observations in the He
I 10830 Å spectral region of a FER were recorded with GRIS at the
1.5 m aperture GREGOR telescope. A Milne-Eddington-based inversion
code was employed to extract the photospheric information of the Si I
spectral line, whereas the He I triplet line was analyzed with the Hazel
inversion code, which takes into account the joint action of the Hanle
and the Zeeman effects. The spectropolarimetric analysis of the Si I
line reveals a complex magnetic structure near the vicinity of the FER,
where a weak (350-600 G) and horizontal magnetic field was observed. In
contrast to the photosphere, the analysis of the He I triplet presents
a smooth variation of the magnetic field vector (ranging from 100 to
400 G) and velocities across the FER. Moreover, we find supersonic
downflows of ∼40 km s<SUP>-1</SUP> appearing near the foot points
of loops connecting two pores of opposite polarity, whereas strong
upflows of 22 km s<SUP>-1</SUP> appear near the apex of the loops. At
the location of supersonic downflows in the chromosphere, we observed
downflows of 3 km s<SUP>-1</SUP> in the photosphere. Furthermore,
nonforce-free field extrapolations were performed separately at
two layers in order to understand the magnetic field topology of
the FER. We determine, using extrapolations from the photosphere and
the observed chromospheric magnetic field, that the average formation
height of the He I triplet line is ∼2 Mm from the solar surface. The
reconstructed loops using photospheric extrapolations along an arch
filament system have a maximum height of ∼10.5 Mm from the solar
surface with a foot-point separation of ∼19 Mm, whereas the loops
reconstructed using chromospheric extrapolations reach around ∼8.4
Mm above the solar surface with a foot-point separation of ∼16 Mm at
the chromospheric height. The magnetic topology in the FER suggests
the presence of small-scale loops beneath the large loops. Under
suitable conditions, due to magnetic reconnection, these loops can
trigger various heating events in the vicinity of the FER.
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Title: Chromospheric observations and magnetic configuration of a
supergranular structure
Authors: Robustini, Carolina; Esteban Pozuelo, Sara; Leenaarts,
Jorrit; de la Cruz Rodríguez, Jaime
2019A&A...621A...1R Altcode: 2018A&A...621A...1R; 2018arXiv181010762R
Context. Unipolar magnetic regions are often associated with
supergranular cells. The chromosphere above these regions is regulated
by the magnetic field, but the field structure is poorly known. In
unipolar regions, the fibrillar arrangement does not always coincide
with magnetic field lines, and polarimetric observations are needed
to establish the chromospheric magnetic topology. <BR /> Aims: In an
active region close to the limb, we observed a unipolar annular network
of supergranular size. This supergranular structure harbours a radial
distribution of the fibrils converging towards its centre. We aim to
improve the description of this structure by determining the magnetic
field configuration and the line-of-sight velocity distribution in both
the photosphere and the chromosphere. <BR /> Methods: We observed the
supergranular structure at different heights by taking data in the Fe I
6301-6302 Å, Hα, Ca II 8542 Å, and the Ca II H&K spectral lines
with the CRisp Imaging SpectroPolarimeter (CRISP) and CHROMospheric
Imaging Spectrometer (CHROMIS) at the Swedish 1-m Solar Telescope. We
performed Milne-Eddington inversions of the spectropolarimetric data
of Fe I 6301-6302 Å and applied the weak field approximation to Ca
II 8542 Å data to retrieve the magnetic field in the photosphere
and chromosphere. We used photospheric magnetograms of CRISP, Hinode
Solar Optical Telescope spectropolarimeter, and Helioseismic and
Magnetic Imager to calculate the magnetic flux. We investigated the
velocity distribution using the line-of-sight velocities computed
from the Milne-Eddington inversion and from the Doppler shift of the
K<SUB>3</SUB> feature in the Ca II K spectral line. To describe the
typical spectral profiles characterising the chromosphere above the
inner region of the supergranular structure, we performed a K-mean
clustering of the spectra in Ca II K. <BR /> Results: The photospheric
magnetic flux shows that the supergranular boundary has an excess
of positive polarity and the whole structure is not balanced. The
magnetic field vector at chromospheric heights, retrieved by the
weak field approximation, indicates that the field lines within the
supergranular cell tend to point inwards, and might form a canopy
above the unipolar region. In the centre of the supergranular cell
hosting the unipolar region, we observe a persistent chromospheric
brightening coinciding with a strong gradient in the line-of-sight
velocity. <P />The movie associated to Fig. 2 is available at <A
href="https://www.aanda.org/10.1051/0004-6361/201833246/olm">https://www.aanda.org</A>
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Title: The dynamic chromosphere: Results and techniques with an
observational approach
Authors: Robustini, Carolina
2018PhDT........98R Altcode:
No abstract at ADS
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Title: The chromosphere above a δ-sunspot in the presence of
fan-shaped jets
Authors: Robustini, Carolina; Leenaarts, Jorrit; de la Cruz Rodríguez,
Jaime
2018A&A...609A..14R Altcode: 2017A&A...609A..14R; 2017arXiv170903864R
Context. Delta-sunspots are known to be favourable locations for
fast and energetic events like flares and coronal mass ejections. The
photosphere of this sunspot type has been thoroughly investigated in
the past three decades. The atmospheric conditions in the chromosphere
are not as well known, however. <BR /> Aims: This study is focused on
the chromosphere of a δ-sunspot that harbours a series of fan-shaped
jets in its penumbra. The aim of this study is to establish the
magnetic field topology and the temperature distribution in the
presence of jets in the photosphere and the chromosphere. <BR />
Methods: We use data from the Swedish 1m Solar Telescope (SST) and
the Solar Dynamics Observatory. We invert the spectropolarimetric
Fe I 6302 Å and Ca II 8542 Å data from the SST using the non-LTE
inversion code NICOLE to estimate the magnetic field configuration,
temperature, and velocity structure in the chromosphere. <BR />
Results: A loop-like magnetic structure is observed to emerge
in the penumbra of the sunspot. The jets are launched from this
structure. Magnetic reconnection between this emerging field and the
pre-existing vertical field is suggested by hot plasma patches on the
interface between the two fields. The height at which the reconnection
takes place is located between log τ<SUB>500</SUB> = -2 and log
τ<SUB>500</SUB> = -3. The magnetic field vector and the atmospheric
temperature maps show a stationary configuration during the whole
observation. <P />Movies associated to Figs. 3-5 are available at <A
href="http://www.aanda.org/10.1051/0004-6361/201731504/olm">http://www.aanda.org</A>
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Title: Fan-shaped jets above the light bridge of a sunspot driven
by reconnection
Authors: Robustini, Carolina; Leenaarts, Jorrit; de la Cruz Rodriguez,
Jaime; Rouppe van der Voort, Luc
2016A&A...590A..57R Altcode: 2015arXiv150807927R
We report on a fan-shaped set of high-speed jets above a strongly
magnetized light bridge (LB) of a sunspot observed in the Hα line. We
study the origin, dynamics, and thermal properties of the jets using
high-resolution imaging spectroscopy in Hα from the Swedish 1m Solar
Telescope and data from the Solar Dynamics Observatory and Hinode. The
Hα jets have lengths of 7-38 Mm, are impulsively accelerated to a speed
of ~100 km s<SUP>-1</SUP> close to photospheric footpoints in the LB,
and exhibit a constant deceleration consistent with solar effective
gravity. They are predominantly launched from one edge of the light
bridge, and their footpoints appear bright in the Hα wings. Atmospheric
Imaging Assembly data indicates elongated brightenings that are nearly
co-spatial with the Hα jets. We interpret them as jets of transition
region temperatures. The magnetic field in the light bridge has a
strength of 0.8-2 kG and it is nearly horizontal. All jet properties
are consistent with magnetic reconnection as the driver. <P />Movies
associated to Figs. 1 and 2 are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201528022/olm">http://www.aanda.org</A>
