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Author name code: otsuji
ADS astronomy entries on 2022-09-14
author:"Otsuji, Kenichi"
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Title: Universal Correlation between the Ejected Mass and Total
Flare Energy for Solar and Stellar Cold Plasma Ejection
Authors: Kotani, Yuji; Otsuji, Kenichi; Shibata, Kazunari; Asai,
Ayumi; Ichimoto, Kiyoshi; Ishii, Takako; Yamasaki, Daiki
2022cosp...44.2450K Altcode:
We often find spectral signatures of chromospheric plasma ejections
accompanied by flares in various spatial scales in the solar and stellar
atmospheres. Similar spectral signatures are found regardless of their
wide range of scale. However, no physical quantities such as mass and
energy have been estimated for flare energies covering over 10 orders
of magnitude until now. In this study, we analyzed the spectra of
cold plasma ejections associated with flares by performing H$\alpha$
imaging spectroscopy of the solar full-disk with SMART/SDDI. We
determined the ejected mass by cloud model fitting to the H$\alpha$
spectrum. We estimated flare energy by DEM analysis using SDO/AIA
for small-scale flares and by estimating the bolometric energy for
large-scale flares. In addition, we constructed a scaling law for
the total flare energy and the ejected mass and compared it with our
observation. The results are in good agreement with the scaling law for
small mass ejections with small flares in the quiet region for a coronal
field strength of 5 G and filament eruptions with flares for that of 5 -
50 G. We also compared it with the observations interpreted as stellar
filament eruptions, and found that they were roughly consistent with
the scaling law. These results suggest that cold plasma ejections with
flares taking place on the sun and stars in a wide range of the energy
scale are caused by a common mechanism.
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Title: Development of CHARMS (charging and radiation monitors for
space weather) instruments for follow-on Japanese geostationary
meteorological satellite
Authors: Sakaguchi, Kaori; Nagatsuma, Tsutomu; Takashima, Takeshi;
Otsuji, Kenichi; Tsugawa, Takuya; Ishii, Mamoru; Mitani, Takefumi;
Saito, Shinji; Kubo, Yuki; Hozumi, Yuta; Miyake, Hiroaki; Enoki, Kaisei
2022cosp...44.3548S Altcode:
CHARMS (charging and radiation monitors for space weather) is a suite
of sensors measuring energetic electrons (50 keV - 5 MeV) and protons
(10 MeV - 1 GeV), and spacecraft internal charging. It started to be
developed as a hosted payload of follow-on geostationary meteorological
satellite of Japan as know Himawari. CHARMS aims to monitor the
outer radiation belt electrons, solar and galactic protons, that are
hazard to spacecraft operation and radiation exposure of astronauts
and aircrews. To mitigate these risks from space environment hazard,
the space weather forecast service group of the National Institute of
Information and Communications Technology (NICT) plans to utilize the
CHARMS product issuing forecasts and prompt warnings for space weather
users as well as general public. The necessity of operational space
weather monitoring in space is increasingly with the expansion of space
utilization, including social infrastructure, such as navigation,
communication, and broadcasting. CHARMS will be responsible for
operational space-based in-situ observations in geostationary orbit
over Japan after launch scheduled in 2028. Current status of CHARMS
instruments development is introduced in our presentation.
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Title: Relationship between three-dimensional velocity of filament
eruptions and CME association
Authors: Seki, Daikichi; Otsuji, Kenichi; Ishii, Takako T.; Asai,
Ayumi; Ichimoto, Kiyoshi
2021EP&S...73...58S Altcode: 2021arXiv210204578S
It is widely recognised that filament disappearances or eruptions are
frequently associated with Coronal Mass Ejections (CMEs). Since CMEs
are a major source of disturbances of the space environment surrounding
the Earth, it is important to investigate these associations in detail
for the better prediction of CME occurrence. However, the proportion
of filament disappearances associated with CMEs is under debate. The
estimates range from ∼ 10 to ∼ 90% and could be affected by the
manners to select the events. In this study, we aim to reveal what
parameters control the association between filament eruptions and
CMEs. We analysed the relationships between CME associations and the
physical parameters of filaments including their length, maximum
ascending velocity, and direction of eruptions using 28 events of
filament eruptions observed in Hα . We found that the product of the
maximum radial velocity and the filament length is well correlated with
the CME occurrence. If the product is larger than 8.0 ×10<SUP>6</SUP>
km<SUP>2</SUP>s-<SUP>1</SUP>, the filament will become a CME with a
probability of 93%, and if the product is smaller than this value,
it will not become a CME with a probability of 100%. We suggest a
kinetic-energy threshold above which filament eruptions are associated
with CMEs. Our findings also suggest the importance of measuring the
velocity vector of filament eruption in three-dimensional space for
the better prediction of CME occurrence.
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Title: Small-scale Turbulent Motion of the Plasma in a Solar Filament
as the Precursor of Eruption
Authors: Seki, Daikichi; Otsuji, Kenichi; Isobe, Hiroaki; Del Zanna,
Giulio; Ishii, Takako T.; Sakaue, Takahito; Ichimoto, Kiyoshi;
Shibata, Kazunari
2021ApJ...918...38S Altcode: 2021arXiv210611875S
A filament, a dense cool plasma supported by the magnetic fields in
the solar corona, often becomes unstable and erupts. It is empirically
known that the filament often demonstrates some activations such
as a turbulent motion prior to eruption. In our previous study, we
analyzed the Doppler velocity of an Hα filament and found that the
standard deviation of the line-of-sight velocity distribution in a
filament, which indicates the increasing amplitude of the small-scale
motions, increased prior to the onset of the eruption. Here, we
present a further analysis on this filament eruption, which initiated
approximately at 03:40 UT on 2016 November 5 in the vicinity of NOAA
Active Region 12605. It includes a coronal line observation and the
extrapolation of the surrounding magnetic fields. We found that both
the spatially averaged microturbulence inside the filament and the
nearby coronal line emission increased 6 and 10 hr prior to eruption,
respectively. In this event, we did not find any significant changes
in the global potential field configuration preceding the eruption for
the past 2 days, which indicates that there is a case in which it is
difficult to predict the eruption only by tracking the extrapolated
global magnetic fields. In terms of space weather prediction, our
result on the turbulent motions in a filament could be used as the
useful precursor of a filament eruption.
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Title: A three-dimensional velocity of an erupting prominence prior
to a coronal mass ejection
Authors: Gutierrez, Maria V.; Otsuji, Kenichi; Asai, Ayumi; Terrazas,
Raul; Ishitsuka, Mutsumi; Ishitsuka, Jose; Nakamura, Naoki; Yoshinaga,
Yusuke; Morita, Satoshi; Ishii, Takako T.; Ueno, Satoru; Kitai,
Reizaburo; Shibata, Kazunari
2021PASJ...73..394G Altcode: 2021arXiv210108575G; 2021PASJ..tmp...23G
We present a detailed three-dimensional (3D) view of a prominence
eruption, coronal loop expansion, and coronal mass ejections (CMEs)
associated with an M4.4 flare that occurred on 2011 March 8 in the
active region NOAA 11165. Full-disk Hα images of the flare and filament
ejection were successfully obtained by the Flare Monitoring Telescope
(FMT) following its relocation to Ica University, Peru. Multiwavelength
observation around the Hα line enabled us to derive the 3D velocity
field of the Hα prominence eruption. Features in extreme ultraviolet
were also obtained by the Atmospheric Imager Assembly onboard the Solar
Dynamic Observatory and the Extreme Ultraviolet Imager on board the
Solar Terrestrial Relations Observatory - Ahead satellite. We found
that, following collision of the erupted filament with the coronal
magnetic field, some coronal loops began to expand, leading to the
growth of a clear CME. We also discuss the succeeding activities of
CME driven by multiple interactions between the expanding loops and
the surrounding coronal magnetic field.
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Title: Development of new tunable filter for solar observation in
Hida observatory
Authors: Otsuji, Kenichi; Kimura, Gouichi; Nakatani, Yoshi-kazu;
Kaneda, Naoki; Ishii, Takako T.; Hagino, Masaoki; Ichimoto, Kiyoshi
2020SPIE11447E..A5O Altcode:
Solar Magnetic Activity Research Telescope (SMART) at Hida observatory
is in operational to monitor the solar activity. As a new solar Hα
observing instrument for SMART, we developed "Solar Dynamics Doppler
Imager (SDDI)", which can measure the three-dimensional motion of solar
eruptive phenomena. These eruptive events could be affective to the
earth magnetism and cause serious damage to our society. The purpose
of SMART/SDDI is monitoring and forecasting the geo-affective solar
eruptions. In this paper, we present the development of the tunable
filter "F40", the key component of SDDI. The features of TF40 are,
(1) fast tuning of observation wavelength, (2) narrow transmission
width and large free spectral range (FSR), (3) large field-of-view that
covers the entire solar disk with a 20 cm objective lens. TF40 has 7
stages of optical blocks. Each stage consists of a linear polarizer,
calcites, a quartz as half waveplate and a Liquid Crystal Variable
Retarder (LCVR), and has the periodic transmission profile with 0.05,
0.1, 0.2, 0.4, 0.8, 1.6 and 3.2 nm period at Hα line (656.2808 nm),
respectively. Combining the 7 stages, the 0.025 nm transmission
width and 3.2 nm FSR are achieved. Retardation of each LCVR and
its dependence on applied voltage and temperature were measured for
modeling its characteristics, with which we calculate the voltage
for desired retardation. Best-shaped transmission profile is obtained
by further adjustment of voltages of individual LCVRs using the real
solar light. We report the performance and current observing status
of the TF40.
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Title: Synoptic solar observations of the Solar Flare Telescope
focusing on space weather
Authors: Hanaoka, Yoichiro; Sakurai, Takashi; Otsuji, Ken'ichi;
Suzuki, Isao; Morita, Satoshi
2020JSWSC..10...41H Altcode: 2020arXiv200714054H
The solar group at the National Astronomical Observatory of Japan
is conducting synoptic solar observation with the Solar Flare
Telescope. While it is a part of a long-term solar monitoring,
contributing to the study of solar dynamo governing solar activity
cycles, it is also an attempt at contributing to space weather
research. The observations include imaging with filters for Hα, Ca K,
G-band, and continuum, and spectropolarimetry at the wavelength bands
including the He I 1083.0 nm/Si I 1082.7 nm and the Fe I 1564.8 nm
lines. Data for the brightness, Doppler signal, and magnetic field
information of the photosphere and the chromosphere are obtained. In
addition to monitoring dynamic phenomena like flares and filament
eruptions, we can track the evolution of the magnetic fields that
drive them on the basis of these data. Furthermore, the magnetic field
in solar filaments, which develops into a part of the interplanetary
magnetic cloud after their eruption and occasionally hits the Earth,
can be inferred in its pre-eruption configuration. Such observations
beyond mere classical monitoring of the Sun will hereafter become
crucially important from the viewpoint of the prediction of space
weather phenomena. The current synoptic observations with the Solar
Flare Telescope is considered to be a pioneering one for future synoptic
observations of the Sun with advanced instruments.
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Title: SMART/SDDI Filament Disappearance Catalogue
Authors: Seki, Daikichi; Otsuji, Kenichi; Ishii, Takako T.; Hirose,
Kumi; Iju, Tomoya; UeNo, Satoru; Cabezas, Denis P.; Asai, Ayumi;
Isobe, Hiroaki; Ichimoto, Kiyoshi; Shibata, Kazunari
2020arXiv200303454S Altcode:
This paper describes a new SMART/SDDI Filament Disappearance Catalogue,
in which we listed almost all the filament disappearance events
that the Solar Dynamics Doppler Imager (SDDI) has observed since
its installation on the Solar Magnetic Activity Research Telescope
(SMART) in May 2016. Our aim is to build a database that can help
predict the occurrence and severity of coronal mass ejections
(CMEs). The catalogue contains miscellaneous information associated
with filament disappearance such as flare, CME, active region,
three-dimensional trajectory of erupting filaments, detection in
Interplanetary Scintillation (IPS), occurrence of interplanetary CME
(ICME) and Dst index. We also provide statistical information on the
catalogue data. The catalogue is available from the following website:
https://www.kwasan.kyoto-u.ac.jp/observation/event/sddi-catalogue/.
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Title: SMART/SDDI Filament Disappearance Catalogue
Authors: Seki, D.; Otsuji, K.; Ishii, T.; Hirose, K.; Iju, T.; UeNo,
S.; Cabezas, D.; Asai, A.; Isobe, H.; Ichimoto, K.; Shibata, K.
2019SunGe..14...95S Altcode:
This paper describes a new "SMART/SDDI Filament Disappearance
Catalogue," in which we listed almost all the filament disappearance
events that the Solar Dynamics Doppler Imager (SDDI) has observed since
its installation on the Solar Magnetic Activity Research Telescope
(SMART) in May 2016. Our aim is to build a database that can help
predict the occurrence and severity of coronal mass ejections
(CMEs). The catalogue contains miscellaneous information associated
with filament disappearance such as flare, CME, active region,
three-dimensional trajectory of erupting filaments, detection in
Interplanetary Scintillation (IPS), occurrence of interplanetary CME
(ICME) and Dst index. We also provide statistical information on the
catalogue data. The catalogue is available from the following website:
https://www.kwasan.kyoto-u.ac.jp/observation/event/sddi-catalogue/.
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Title: Small-scale motions in solar filaments as the precursors
of eruptions
Authors: Seki, Daikichi; Otsuji, Kenichi; Isobe, Hiroaki; Ishii,
Takako T.; Ichimoto, Kiyoshi; Shibata, Kazunari
2019PASJ...71...56S Altcode: 2019arXiv190208718S; 2019PASJ..tmp...48S
Filaments, the dense cooler plasma floating in the solar corona
supported by magnetic fields, generally exhibit certain activations
before they erupt. In our previous study (Seki et al. 2017, ApJ, 843,
L24), we observed that the standard deviation of the line-of-sight (LOS)
velocities of the small-scale motions in a filament increased prior
to its eruption. However, because that study only analyzed one event,
it is unclear whether such an increase in the standard deviation of
LOS velocities is common in filament eruptions. In this study, 12
filaments that vanished in Hα line center images were analyzed in
a manner similar to the one in our previous work; these included two
quiescent filaments, four active region filaments, and six intermediate
filaments. We verified that in all the 12 events, the standard deviation
of the LOS velocities increased before the filaments vanished. Moreover,
we observed that the quiescent filaments had approximately 10 times
longer duration of an increase in the standard deviation than the
other types of filaments. We concluded that the standard deviation
of the LOS velocities of the small-scale motions in a filament can
potentially be used as a precursor of a filament eruption.
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Title: Revisiting Kunitomo's Sunspot Drawings During 1835 - 1836
in Japan
Authors: Fujiyama, Masashi; Hayakawa, Hisashi; Iju, Tomoya; Kawai,
Toshiki; Toriumi, Shin; Otsuji, Kenichi; Kondo, Katsuya; Watanabe,
Yusaku; Nozawa, Satoshi; Imada, Shinsuke
2019SoPh..294...43F Altcode: 2019arXiv190303092F
We revisit the sunspot drawings made by the Japanese astronomer Kunitomo
Toubei during 1835 - 1836 and recount the sunspot group number for each
image. There are two series of drawings, preliminary (P , containing
17 days with observations) and summary (S , covering 156 days with
observations), all made using brush and ink. S is a compilation of
drawings for the period from February 1835, to March 1836. Presently,
the P drawings are available only for one month, September 1835;
those of other periods have presumably been lost. Another drawing
(I ) lets us recover the raw group count (RGC) for 25 September 1836,
on which the RGC has not been registered in the existing catalogs. We
also revise the RGCs from P and S using the Zürich classification and
determine that Kunitomo's results tend to yield smaller RGCs than those
of other contemporary observers. In addition, we find that Kunitomo's
RGCs and spot areas have a correlation (0.71) that is not very different
from the contemporary observer Schwabe (0.82). Although Kunitomo's spot
areas are much larger than those determined by Schwabe due to skill and
instrument limitations, Kunitomo at least captured the growing trend
of the spot activity in the early phase of Solar Cycle 8. We also
determine the solar rotation axis to estimate the accurate position
(latitude and longitude) of the sunspot groups in Kunitomo's drawings.
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Title: Space Weather Prediction from the Ground: Case of CHAIN
Authors: Seki, Daikichi; Ueno, Satoru; Isobe, Hiroaki; Otsuji, Kenichi;
Cabezas, Denis P.; Ichimoto, Kiyoshi; Shibata, Kazunari; Chain Team
2018SunGe..13..157S Altcode:
In this article, we insist on the importance and the challenges of the
prediction of solar eruptive phenomena including flares, coronal mass
ejections (CME), and filament eruptions fully based on the ground-based
telescopes. It is true that satellites' data are indispensable for the
space weather prediction, but they are vulnerable to the space weather
effects. Therefore, the ground-based telescopes can be complementary
to them from the viewpoint of space weather prediction. From this
view point, one possible new flare prediction method that makes use of
H-alpha, red wings, and blue wings images obtained by the SDDI/SMART,
the ground-based telescope at Hida Observatory, is presented. And
in order to show the possibility for the actual operation based on
that method, the recent progress of CHAIN project, the international
observation network, is mentioned in terms of their outcomes and
capacity buildings.
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Title: Infrared spectro-polarimeter on the Solar Flare Telescope
at NAOJ/Mitaka
Authors: Sakurai, Takashi; Hanaoka, Yoichiro; Arai, Takehiko; Hagino,
Masaoki; Kawate, Tomoko; Kitagawa, Naomasa; Kobiki, Toshihiko;
Miyashita, Masakuni; Morita, Satoshi; Otsuji, Ken'ichi; Shinoda,
Kazuya; Suzuki, Isao; Yaji, Kentaro; Yamasaki, Takayuki; Fukuda,
Takeo; Noguchi, Motokazu; Takeyama, Norihide; Kanai, Yoshikazu;
Yamamuro, Tomoyasu
2018PASJ...70...58S Altcode: 2018PASJ..tmp...63S; 2018PASJ..tmp...82S
An infrared spectro-polarimeter installed on the Solar Flare Telescope
at the Mitaka headquarters of the National Astronomical Observatory of
Japan is described. The new spectro-polarimeter observes the full Sun
via slit scans performed at two wavelength bands, one near 1565 nm for a
Zeeman-sensitive spectral line of Fe I and the other near 1083 nm for He
I and Si I lines. The full Stokes profiles are recorded; the Fe I and Si
I lines give information on photospheric vector magnetic fields, and the
helium line is suitable for deriving chromospheric magnetic fields. The
infrared detector we are using is an InGaAs camera with 640 × 512
pixels and a read-out speed of 90 frames s<SUP>-1</SUP>. The solar
disk is covered by two swaths (the northern and southern hemispheres)
of 640 pixels each. The final magnetic maps are made of 1200 × 1200
pixels with a pixel size of 1{^”<SUB>.</SUB>}8. We have been carrying
out regular observations since 2010 April, and have provided full-disk,
full-Stokes maps, at the rate of a few maps per day, on the internet.
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Title: Space Weather Prediction from the Ground: Case of CHAIN
Authors: Seki, Daikichi; Ueno, Satoru; Isobe, Hiroaki; Otsuji, Kenichi;
Cabezas, Denis P.; Ichimoto, Kiyoshi; Shibata, Kazunari; CHAIN team
2018arXiv180806295S Altcode:
In this article, we insist on the importance and the challenges of the
prediction of solar eruptive phenomena including flares, coronal mass
ejections (CME), and filament eruptions fully based on the ground-based
telescopes. It is true that satellites' data are indispensable for the
space weather prediction, but they are vulnerable to the space weather
effects. Therefore, the ground-based telescopes can be complementary
to them from the viewpoint of space weather prediction. From this
view point, one possible new flare prediction method that makes use of
H-alpha, red wings, and blue wings images obtained by the SDDI/SMART,
the ground-based telescope at Hida Observatory, is presented. And
in order to show the possibility for the actual operation based on
that method, the recent progress of CHAIN project, the international
observation network, is mentioned in terms of their outcomes and
capacity buildings.
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Title: Increase in the Amplitude of Line-of-sight Velocities of the
Small-scale Motions in a Solar Filament before Eruption
Authors: Seki, Daikichi; Otsuji, Kenichi; Isobe, Hiroaki; Ishii,
Takako T.; Sakaue, Takahito; Hirose, Kumi
2017ApJ...843L..24S Altcode: 2017arXiv170509041S
We present a study on the evolution of the small-scale velocity field
in a solar filament as it approaches the eruption. The observation
was carried out by the Solar Dynamics Doppler Imager (SDDI) that was
newly installed on the Solar Magnetic Activity Research Telescope at
Hida Observatory. The SDDI obtains a narrowband full-disk image of
the Sun at 73 channels from Hα - 9.0 Å to Hα + 9.0 Å, allowing us
to study the line-of-sight (LOS) velocity of the filament before and
during the eruption. The observed filament is a quiescent filament
that erupted on 2016 November 5. We derived the LOS velocity at each
pixel in the filament using the Becker’s cloud model, and made the
histograms of the LOS velocity at each time. The standard deviation
of the LOS velocity distribution can be regarded as a measure for the
amplitude of the small-scale motion in the filament. We found that
the standard deviation on the previous day of the eruption was mostly
constant around 2-3 km s<SUP>-1</SUP>, and it slightly increased to
3-4 km s<SUP>-1</SUP> on the day of the eruption. It shows a further
increase, with a rate of 1.1 m s<SUP>-2</SUP>, about three hours before
eruption, and another increase, with a rate of 2.8 m s<SUP>-2</SUP>,
about an hour before eruption. From this result we suggest that the
increase in the amplitude of the small-scale motions in a filament
can be regarded as a precursor of the eruption.
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Title: A New Solar Imaging System for Observing High-Speed Eruptions:
Solar Dynamics Doppler Imager (SDDI)
Authors: Ichimoto, Kiyoshi; Ishii, Takako T.; Otsuji, Kenichi; Kimura,
Goichi; Nakatani, Yoshikazu; Kaneda, Naoki; Nagata, Shin'Ichi; UeNo,
Satoru; Hirose, Kumi; Cabezas, Denis; Morita, Satoshi
2017SoPh..292...63I Altcode:
A new solar imaging system was installed at Hida Observatory to
observe the dynamics of flares and filament eruptions. The system (Solar
Dynamics Doppler Imager; SDDI) takes full-disk solar images with a field
of view of 2520 arcsec×2520 arcsec at multiple wavelengths around
the H α line at 6562 Å. Regular operation was started in May 2016,
in which images at 73 wavelength positions spanning from H α −9 Å
to H α +9 Å are obtained every 15 seconds. The large dynamic range
of the line-of-sight velocity measurements (±400 kms−<SUP>1</SUP>)
allows us to determine the real motions of erupting filaments in
3D space. It is expected that SDDI provides unprecedented datasets
to study the relation between the kinematics of filament eruptions
and coronal mass ejections (CME), and to contribute to the real-time
prediction of the occurrence of CMEs that cause a significant impact
on the space environment of the Earth.
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Title: “Dandelion” Filament Eruption and Coronal Waves Associated
with a Solar Flare on 2011 February 16
Authors: Cabezas, Denis P.; Martínez, Lurdes M.; Buleje, Yovanny J.;
Ishitsuka, Mutsumi; Ishitsuka, José K.; Morita, Satoshi; Asai, Ayumi;
UeNo, Satoru; Ishii, Takako T.; Kitai, Reizaburo; Takasao, Shinsuke;
Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari
2017ApJ...836...33C Altcode: 2017arXiv170100308C
Coronal disturbances associated with solar flares, such as Hα Moreton
waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves,
are discussed herein in relation to magnetohydrodynamic fast-mode
waves or shocks in the corona. To understand the mechanism of
coronal disturbances, full-disk solar observations with high spatial
and temporal resolution over multiple wavelengths are of crucial
importance. We observed a filament eruption, whose shape is like a
“dandelion,” associated with the M1.6 flare that occurred on 2011
February 16 in Hα images taken by the Flare Monitoring Telescope at
Ica University, Peru. We derive the three-dimensional velocity field
of the erupting filament. We also identify winking filaments that are
located far from the flare site in the Hα images, whereas no Moreton
wave is observed. By comparing the temporal evolution of the winking
filaments with those of the coronal wave seen in the EUV images data
taken by the Atmospheric Imaging Assembly on board the Solar Dynamics
Observatory and by the Extreme Ultraviolet Imager on board the Solar
Terrestrial Relations Observatory-Ahead, we confirm that the winking
filaments were activated by the EUV coronal wave.
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Title: Development of the Universal Tunable Filter and High-resolution
Imaging Observation with the Fuxian Solar Observatory
Authors: Hagino, M.; Ichimoto, K.; Ueno, S.; Kimura, G.; Otsuji, K.;
Kitai, R.; Zhong, L.; Xu, Z.; Shinoda, K.; Hara, H.; Suematsu, Y.;
Shimizu, T.
2016ASPC..504..103H Altcode:
We have developed a new narrow-band universal tunable filter to perform
imaging spectroscopy of the solar chromosphere. The development stage
of the filter has been almost finished and we shifted to the scientific
observation phase by using large grand-based telescopes. Using the
filter, a series of high-resolution images were obtained with the 1m
vacuum solar telescope at the Fuxian Solar Observatory. We succeeded in
observing several flares and fine structures of the chromospheric layer.
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Title: A Real Source of a Stealth CME - Energetics of a Filament
Eruption and Giant Arcade Formation
Authors: Asai, Ayumi; Ishii, Takako T.; Otsuji, Kenichi; Ichimoto,
Kiyoshi; Shibata, Kazunari
2015IAUGA..2255125A Altcode:
Various active phenomena occurring on the solar surface are sources
of disturbances in the solar-terrestrial environment. It is, however,
sometimes said that solar flares, the most energetic explosions in the
active phenome on the sun, are not crucially important for space weather
researches, but coronal mass ejections (CMEs) are more significant. This
is because not all flares are associated with CMEs, and therefore, not
geo-effective, and because geo-effective CMEs sometimes occur without
any notable active phenomena (such as flares) on the sun. The latter
is sometimes called as a “stealth CME” event. However, for even
such cases, we often see filament eruptions in H-alpha observations
and formations of giant arcade in X-ray and/or extreme ultraviolet
(EUV) observations.The geomagnetic storm with the Dst index of -105
nT that occurred on October 8, 2012 was such a stealth event. We,
on the other hand, recognize formation of an X-ray giant arcade and
activation of an H-alpha filament on October 5, 2012. We examined the
velocity field of the filament by using the H-alpha wing data obtained
with SMART telescope at Hida Observatory, Kyoto University. We also
derived the temperature and the volume emission measure by using the
X-ray and EUV data obtained by Hinode/XRT and SDO/AIA. We discuss the
energetics of this event on the solar surface
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Title: A statistical analysis of current helicity and twist in
solar active regions over the phases of the solar cycle using the
spectro-polarimeter data of Hinode
Authors: Otsuji, Kenichi; Sakurai, Takashi; Kuzanyan, Kirill
2015PASJ...67....6O Altcode: 2014arXiv1410.7532O; 2014PASJ..tmp..137O
Current helicity and twist of solar magnetic fields are important in
characterizing the dynamo mechanism working in the convection zone of
the Sun. We have carried out a statistical study on the current helicity
of solar active regions observed with the spectro-polarimeter (SP) of
the Hinode Solar Optical Telescope (SOT). We used SOT-SP data of 558
vector magnetograms of a total of 80 active regions obtained during
the period from 2006 to 2012. We have applied spatial smoothing and
division of data points into weak and strong field ranges to compare
the contributions from different scales and field strengths. We
found that the current helicity follows the "hemispheric sign rule"
when weak magnetic fields (absolute field strength < 300 gauss)
are considered and no smoothing is applied. On the other hand, the
pattern of current helicity fluctuates and violates the hemispheric
sign rule when stronger magnetic fields are considered and smoothing
of 2{^”<SUB>.</SUB>}0 (modeled on ground-based observations) is
applied. Furthermore, we found a tendency that weak and inclined
fields conform to the hemispheric sign rule and strong and vertical
fields violate it. These different properties of helicity through
the strong and weak magnetic field components give important clues in
understanding the solar dynamo as well as the mechanism of formation
and evolution of solar active regions.
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Title: Formation and Decay of Rudimentary Penumbra around a Pore
Authors: Watanabe, Hiroko; Kitai, Reizaburo; Otsuji, Kenichi
2014ApJ...796...77W Altcode:
We analyze the evolution of a pore in the active region NOAA 10940
using the data obtained by the Hinode satellite on 2007 February
3. The pore we analyzed showed the formation of a rudimentary penumbra
structure, succeeded by an abrupt disappearance after about 5 hr. The
pore had an approximate radius of 3.5 Mm and a total magnetic flux
of 3.0 × 10<SUP>19</SUP> Mx, which is a little smaller than the
necessary magnetic flux for penumbral formation supposed by Rucklidge
et al. (1-1.5 × 10<SUP>20</SUP> Mx). Our observation describes
a rare phenomenon which was in the unstable phase between a pore
and a sunspot. The area of the dark umbra gradually decreased when
the rudimentary penumbral filaments formed the penumbral structure,
meaning that the penumbra develops at the expense of the umbral magnetic
flux. This statement was confirmed by a rough estimation of the magnetic
flux variation observed by the Hinode Fe I magnetogram. Five hours after
the formation phase, the decay phase began. In this decaying phase,
multiple opposite polarity patches are found to appear in the exterior
of the pore (a different location from the penumbra formation site). We
interpret these opposite polarities as signatures of the horizontal
magnetic field, which preferably appears in the course of the unstable
reconfiguration of the magnetic field structure. During the course of
the disappearance of the penumbra, the horizontal penumbral field seems
to become vertical because of the dark umbral area that recovered by
about 10%.
---------------------------------------------------------
Title: Morphological study of penumbral formation
Authors: Kitai, Reizaburo; Watanabe, Hiroko; Otsuji, Ken'ichi
2014PASJ...66S..11K Altcode: 2014PASJ..tmp...96K; 2014arXiv1407.4573K
Penumbrae are known to be areas of mainly horizontal magnetic field
surrounding umbrae of relatively large and mature sunspots. In this
paper, we observationally studied the formation of penumbrae in NOAA
10978, where several penumbral formations were observed in G-band
images of the Solar Optical Telescope on board Hinode. Thanks to the
continuous observation by Hinode, we could morphologically follow the
evolution of sunspots and found that there are several paths to the
penumbral formation: (1) active accumulation of magnetic flux, (2) rapid
emergence of magnetic field, and (3) appearance of twisted or rotating
magnetic tubes. In all of these cases, magnetic fields are expected
to sustain high inclination at the edges of flux tube concentration
longer than the characteristic growth time of downward magnetic pumping.
---------------------------------------------------------
Title: Within the International Collaboration CHAIN: a Summary of
Events Observed with Flare Monitoring Telescope (FMT) in Peru
Authors: Ishitsuka, J.; Asai, A.; Morita, S.; Terrazas, R.; Cabezas,
D.; Gutierrez, V.; Martinez, L.; Buleje, Y.; Loayza, R.; Nakamura,
N.; Takasao, S.; Yoshinaga, Y.; Hillier, A.; Otsuji, K.; Shibata, K.;
Ishitsuka, M.; Ueno, S.; Kitai, R.; Ishii, T.; Ichimoto, K.; Nagata,
S.; Narukage, N.
2014SunGe...9...85I Altcode:
In 2008 we inaugurated the new Solar Observatory in collaboration with
Faculty of Sciences of San Luis Gonzaga de Ica National University,
300 km south of Lima. In March of 2010 a Flare Monitoring Telescope
of Hida Observatory of Kyoto University arrived to Ica, part of CHAIN
Project (Continuous H-alpha Imaging Network). In October of the same
year we hosted the First FMT Workshop in Ica, then in July of 2011 the
Second FMT Workshop was opened. Since that we are focused on two events
registered by FMT in Peru to publish results. FMT is a good tool to
introduce young people from universities into scientific knowledge;
it is good also for education in Solar Physics and outreach. Details
of this successful collaboration will be explained in this presentation.
---------------------------------------------------------
Title: Chromospheric Anemone Jets Observed with Hinode/SOT and Hida
Ca II Spectroheliograph
Authors: Morita, S.; Shibata, K.; Ueno, S.; Ichimoto, K.; Kitai, R.;
Otsuji, K.
2012ASPC..454...95M Altcode:
We present the first simultaneous observations of chromospheric
“anemone” jets in active regions with the Ca II H broadband
filetergram on the Hinode/SOT and with the Ca II K spetroheliogram on
the Domeless Solar Telescope (DST) at the Hida Observatory. During
coordinated observation period, 9 chromospheric anemone jets were
simultaneously observed with the two instruments. These observations
revealed: (1) the jets are generated in the low chromosphere because
these cannot be seen in Ca II K<SUB>3</SUB>, (2) these jets are
associated with mixed polarity regions which are either small emerging
flux regions or moving magnetic features, (3) the Ca II K line often
show red or blue asymmetry in K<SUB>2</SUB>/K<SUB>1</SUB> component;
the footpoint of the jets associated with emerging flux regions often
show red asymmetry (2-16 km s<SUP>-1</SUP>), while the one with moving
magnetic features show blue asymmetry (∼5 km s<SUP>-1</SUP>). The
magnetic cancellations were observed at the footpoint of the jets. The
canceling rates are of order of 10<SUP>16</SUP> Mx s<SUP>-1</SUP>, and
the resulting magnetic energy release rate (1.1-10)×10<SUP>24</SUP> erg
s<SUP>-1</SUP>, with the total energy release (1-13)×10<SUP>26</SUP>
erg for the duration of the magnetic cancellations, ∼130 s. These
are comparable to the estimated total energy, ∼10<SUP>26</SUP> erg,
in a single chromospheric anemone jet.
---------------------------------------------------------
Title: Statistical Study on the Nature of Solar-Flux Emergence
Authors: Otsuji, Kenichi; Kitai, Reizaburo; Ichimoto, Kiyoshi;
Shibata, Kazunari
2011PASJ...63.1047O Altcode: 2011arXiv1106.1955O
We studied 101 flux emergence events ranging from small ephemeral
regions to large emerging flux regions that were observed with the
Hinode Solar Optical Telescope filtergram. We investigated how the
total magnetic flux of the emergence event controls the nature of
emergence. To determine the modes of emergences, horizontal velocity
fields of the global motion of the magnetic patches in the flux emerging
sites were measured by local correlation tracking. Between two main
polarities of the large emerging flux regions with more than around 2
× 10<SUP>19</SUP> Mx, there were converging flows of anti-polarity
magnetic patches. On the other hand, small ephemeral regions showed
no converging flow, but a simple diverging pattern. When we looked
into the detailed features in the emerging sites, irrespective of
the total flux and the spatial size, all of the emergence events
were observed to consist of single or multiple elementary emergence
unit(s). The typical size of unitary emergence is 4 Mm, and consistent
with simulation results. From a statistical study of the flux emergence
events, the maximum spatial distance between two main polarities, the
magnetic flux growth rate and the mean separation speed were found
to follow the power-law functions of the total magnetic flux with
indices of 0.27, 0.57, and -0.16, respectively. From a discussion on
the observed power-law relations, we obtained a physical view of solar
flux emergence, in which the emerging magnetic fields float and evolve
while balancing to the surrounding turbulent atmosphere.
---------------------------------------------------------
Title: Observations of Chromospheric Anemone Jets with Hinode Ca II
Broadband Filtergraph and Hida Ca II Spectroheliograph
Authors: Morita, Satoshi; Shibata, Kazunari; UeNo, Satoru; Ichimoto,
Kiyoshi; Kitai, Reizaburo; Otsuji, Ken-ichi
2010PASJ...62..901M Altcode: 2010arXiv1002.2143M
We present the first simultaneous observations of chromospheric
"anemone" jets in solar active regions with Hinode SOT Ca II H
broadband filetergram and Ca II K spetroheliogram on the Domeless
Solar Telescope (DST) at Hida Observatory. During the coordinated
observation, 9 chromospheric anemone jets were simultaneously observed
with the two instruments. These observations revealed three important
features, i.e.: (1) the jets are generated in the lower chromosphere,
(2) the length and lifetime of the jets are 0.4-5 Mm and 40-320 sec,
(3) the apparent velocity of the jets with Hinode SOT are 3-24 km/s,
while Ca II K3 component at the jets show blueshifts (in 5 events) in
the range of 2- 6 km/s. The chromospheric anemone jets are associated
with mixed polarity regions which are either small emerging flux regions
or moving magnetic features. It is found that the Ca II K line often
show red or blue asymmetry in K2/K1 component: the footpoint of the
jets associated with emerging flux regions often show redshift (2-16
km/s), while the one with moving magnetic features show blueshift
(around 5 km/s). Detailed analysis of magnetic evolution of the jet
foaming regions revealed that the reconnection rate (or canceling
rate) of the total magnetic flux at the footpoint of the jets are of
order of 10^{16} Mx/s, and the resulting magnetic energy release rate
(1.1-10) x 10^{24} erg/s, with the total energy release (1-13) x 10^{26}
erg for the duration of the magnetic cancellations, 130s. These are
comparable to the estimated total energy, 10^{26} erg, in a single
chromospheric anemone jet. An observation-based physical model of the
jet is presented. The relation between chromospheric anemone jets and
Ellerman bombs is discussed.
---------------------------------------------------------
Title: Internal Fine Structure of Ellerman Bombs
Authors: Hashimoto, Yuki; Kitai, Reizaburo; Ichimoto, Kiyoshi; Ueno,
Satoru; Nagata, Shin'ichi; Ishii, Takako T.; Hagino, Masaoki; Komori,
Hiroyuki; Nishida, Keisuke; Matsumoto, Takuma; Otsuji, Kenichi;
Nakamura, Tahei; Kawate, Tomoko; Watanabe, Hiroko; Shibata, Kazunari
2010PASJ...62..879H Altcode:
We conducted coordinated observations of Ellerman bombs (EBs) between
Hinode Satellite and Hida Observatory (HOP12). CaII H broad-band
filter images of NOAA 10966 on 2007 August 9 and 10 were obtained
with the Solar Optical Telescope (SOT) aboard the Hinode Satellite,
and many bright points were observed. We identified a total of 4
bright points as EBs, and studied the temporal variation of their
morphological fine structures and spectroscopic characteristics. With
high-resolution CaII H images of SOT, we found that the EBs, thus far
thought of as single bright features, are composed of a few of fine
subcomponents. Also, by using Stokes I/V filtergrams with Hinode/SOT,
and CaII H spectroheliograms with Hida/Domeless Solar Telescope (DST),
our observation showed: (1) The mean duration, the mean width, the
mean length, and the mean aspect ratio of the subcomponents were
390 s, 170 km, 450 km, and 2.7, respectively. (2) Subcomponents
started to appear on the magnetic neutral lines, and extended their
lengths from the original locations. (3) When the CaII H line of EBs
showed the characteristic blue asymmetry, they are associated with the
appearance or re-brightening of subcomponents. Summarizing our results,
we obtained an observational view that elementary magnetic reconnections
take place one by one successively and intermittently in EBs, and that
their manifestation is the fine subcomponents of the EB phenomena.
---------------------------------------------------------
Title: Spicule Dynamics over a Plage Region
Authors: Anan, Tetsu; Kitai, Reizaburo; Kawate, Tomoko; Matsumoto,
Takuma; Ichimoto, Kiyoshi; Shibata, Kazunari; Hillier, Andrew; Otsuji,
Kenichi; Watanabe, Hiroko; Ueno, Satoru; Nagata, Shin'ichi; Ishii,
Takako T.; Komori, Hiroyuki; Nishida, Keisuke; Nakamura, Tahei; Isobe,
Hiroaki; Hagino, Masaoki
2010PASJ...62..871A Altcode: 2010arXiv1002.2288A
We studied spicular jets over a plage area and derived their
dynamic characteristics using Hinode Solar Optical Telescope (SOT)
high-resolution images. A target plage region was near to the west limb
of the solar disk. This location permitted us to study the dynamics
of spicular jets without any overlapping effect of spicular structures
along the line of sight. In this work, to increase the ease with which
we could identify spicules on the disk, we applied the image processing
method `MadMax' developed by Koutchmy et al. (1989). It enhances fine,
slender structures (like jets), over a diffuse background. We identified
169 spicules over the target plage. This sample permited us to derive
statistically reliable results regarding spicular dynamics. The
properties of plage spicules can be summarized as follows: (1) In a
plage area, we clearly identified spicular jet features. (2) They were
shorter in length than the quiet region limb spicules, and followed a
ballistic motion under constant deceleration. (3) The majority (80%)
of the plage spicules showed a cycle of rise and retreat, while 10% of
them faded out without a complete retreat phase. (4) The deceleration
of the spicule was proportional to the velocity of ejection (i.e.,
the initial velocity).
---------------------------------------------------------
Title: CaII K Spectral Study of an Emerging Flux Region using the
Domeless Solar Telescope in Hida Observatory
Authors: Otsuji, Kenichi; Kitai, Reizaburo; Matsumoto, Takuma;
Ichimoto, Kiyoshi; Ueno, Satoru; Nagata, Shin'ichi; Isobe, Hiroaki;
Shibata, Kazunari
2010PASJ...62..893O Altcode: 2010arXiv1005.2025O
A cooperative observation with Hida Observatory and the Hinode
satellite was performed on an emerging flux region. Successive CaII
K spectro-heliograms of the emerging flux region were taken by the
Domeless Solar Telescope of Hida Observatory. Hinode observed the
emerging flux region with CaII H and FeI Stokes IQUV filtergrams. In
this study, detailed dynamics and the temporal evolution of the
magnetic flux emergence was studied observationally. The event was first
detected in the photospheric magnetic field signals; 3 minutes later,
a horizontal expansion of the dark area was detected. Then, 7 minutes
later than the horizontal expansion, the emerging loops were detected
with a maximal rise speed of 2.1 km s<SUP>-1</SUP> at chromospheric
heights. The observed dynamics of the emerging magnetic flux from the
photosphere to the upper chromosphere was very consistent with the
results of previous simulation studies. A gradual rising phase of flux
tubes with a weak magnetic strength was confirmed by our observation.
---------------------------------------------------------
Title: Emergence of Helical Flux and the Formation of an Active
Region Filament Channel
Authors: Lites, B. W.; Kubo, M.; Berger, T.; Frank, Z.; Shine, R.;
Tarbell, T.; Title, A.; Okamoto, T. J.; Otsuji, K.
2010ApJ...718..474L Altcode:
We present comprehensive observations of the formation and evolution
of a filament channel within NOAA Active Region (AR) 10978 from
Hinode/Solar Optical Telescope and TRACE. We employ sequences
of Hinode spectro-polarimeter maps of the AR, accompanying Hinode
Narrowband Filter Instrument magnetograms in the Na I D1 line, Hinode
Broadband Filter Instrument filtergrams in the Ca II H line and G-band,
Hinode X-ray telescope X-ray images, and TRACE Fe IX 171 Å image
sequences. The development of the channel resembles qualitatively
that presented by Okamoto et al. in that many indicators point to
the emergence of a pre-existing sub-surface magnetic flux rope. The
consolidation of the filament channel into a coherent structure takes
place rapidly during the course of a few hours, and the filament form
then gradually shrinks in width over the following two days. Particular
to this filament channel is the observation of a segment along its
length of horizontal, weak (500 G) flux that, unlike the rest of the
filament channel, is not immediately flanked by strong vertical plage
fields of opposite polarity on each side of the filament. Because this
isolated horizontal field is observed in photospheric lines, we infer
that it is unlikely that the channel formed as a result of reconnection
in the corona, but the low values of inferred magnetic fill fraction
along the entire length of the filament channel suggest that the bulk
of the field resides somewhat above the low photosphere. Correlation
tracking of granulation in the G band presents no evidence for either
systematic flows toward the channel or systematic shear flows along
it. The absence of these flows, along with other indications of these
data from multiple sources, reinforces (but does not conclusively
demonstrate) the picture of an emerging flux rope as the origin of
this AR filament channel.
---------------------------------------------------------
Title: Solar Plages: Observational Study of Their Chromospheric
Heating and Spicular Mass Ejections
Authors: Kitai, R.; Hashimoto, Y.; Anan, T.; Matsumoto, T.; Kawate,
T.; Watanabe, H.; Otsuji, K.; Nakamura, T.; Nishizuka, N.; Nishida,
K.; Ueno, S.; Nagata, S.; Shibata, K.
2009ASPC..415...19K Altcode:
We investigated the chromospheric dynamics of plage area. From our
spectroscopic analysis of the CaII K line, we have found that their
periodic variations are due to the propagation of acoustic waves from
the lower layers. Another observational work on Hinode CaII H images,
gave us a new result that there are numerous spicular jets in plage
area, thanks to the stable observing condition of Hinode. The present
paper is an extended abstract of our works which will be published
fully in our future papers.
---------------------------------------------------------
Title: The tandem Fabry Perot Full-Disk Solar Vector Magnetogram
system for the Solar Magnetic Activity Research Telescope (SMART)
Authors: Otsuji, K.; Nagata, S.; Ueno, S.; Kitai, R.; Kimura, G.;
Nakatani, Y.; Ishii, T.; Morita, S.; Shibata, K.
2009AGUFMSH33B1498O Altcode:
For solar and heliospheric physics, energy release mechanism of
solar flares and onset of CMEs are one of the most the most important
issues. Solar Magnetic Activity Research Telescope (SMART) in Hida
observatory Kyoto University aims to investigate the relation between
the solar flares and photospheric vector magnetic field. Full disk high
resolution H-alpha images as well as and photospheric vector magnetic
field using Fe I 6302 line have been taken regularly since 2005. In
order to improve the vector magnetic field measurement accuracy,
a tandem Fabry Perot Stokes polarimeter is newly constructed for
the SMART. The system consist of a tandem FP with FWHM of ~0.01nm,
polarization beam splitter and two CCD cameras taking orthogonally
polarized images simultaneously. In this poster we present the
system design and laboratory test results, and expected observational
capabilities. We also present the flux emergence activities observed
with SMART and Hinode satellite.
---------------------------------------------------------
Title: The tandem Fabry-Perot filter imaging spectro-polarimeter
for the Solar Magnetic Activity Research Telescope (SMART)
Authors: Nagata, Shin'ichi; Otsuji, Kenichi; Ishii, Takako T.;
Ichimoto, Kiyoshi; Ueno, Satoru; Kitai, Reizaburo; Kimura, Goichi;
Shibata, Kazunari; Nakatani, Yoshikazu; Morita, Satoshi
2009SPIE.7438E..0VN Altcode: 2009SPIE.7438E..22N
In order to perform precise and high time cadence magnetic field
measurement across the solar surface, the Tandem Fabry-Perot filter
imaging spectro-polarimeter for the Solar Magnetic Activity Research
Telescope (SMART) is revised. By using the CCD with moderate frame
rate of 30fps, full Stokes vectors on the field-of-view 320"x240" can
be obtained at 4 wavelengths around FeI6302 line within about 15s. The
optical performance of the Tandem Fabry-Perof filters is investigated
by using the spectrograph at the Domeless Solar Telescope at Hida
Observatory. The test results show the full-width-half-maximum (FWHM)
of the tandem filters is about 0.017nm over the 60mm clear aperture
is achieved. The system is developed to start the regular observations
from 2010.
---------------------------------------------------------
Title: Cooperative observation of solar atmospheric heating by Hida
observatory and Hinode
Authors: Kitai, R.; Hashimoto, Y.; Anan, T.; Watanabe, H.; Ishii,
T. T.; Kawate, T.; Matsumoto, T.; Otsuji, K.; Nakamura, T.; Morita,
S.; Nishizuka, N.; Nishida, K.; Ueno, S.; Nagata, S.; Ichimoto, K.;
Shibata, K.
2008AGUFMSH41B1625K Altcode:
At Hida observatory of Kyoto University, we continue to study solar
activities and fine structures with Domeless Solar Telescope (DST)
and Solar Magnetic Activity Research Telescope (SMART). In this work,
we will report some recent cooperative observational results with
Hinode on the following topics: (1) Plage heating and waves Analysis
of a long time series of CaII K spectrograms at a plage area showed
us a clear co-existence of 3- and 5-min oscillation in Doppler
velocity. We simulated the response of the VAL model atmosphere to
the input of 3-min/5-min acoustic disturbances, in 1-D geometry and
found that plage chromosphere is heated unsteadily by acoustic shock
waves as was proposed by Carlsson and Stein (1997). (2) Disk spicules
in and around plage regions We clearly identified numerous ejecting
features in a plage area. Their morphological shapes of thin tapered
cylinder and their dynamics strongly suggest that they are spicules
in plage area. Plage spicules were observed to move under constant
deceleration, which are driven by acoustic shock waves predicted by
Shibata and Suematsu (1980) and Hansteen et al. (2007). Our results
will be discussed from the view point of Type I, II classification
of limb spicules ( de Pontieu et al. 2007). (3) Umbral dots We have
confirmed that umbral dots are manifestation of magneto-convection in
strong magnetic filed from the analysis of Hinode/SOT/BFI&SP. We
will discuss the plausibility of monolithic umbral model from the
oscillatory brightening of umbral dots. (4) X-ray brightenings in the
supergranular network XRT showed us numerous bright points in solar
quiet regions. Possible relation between these XBPs and supergranular
network pattern in quiet chromosphere was studied. XBPs were found to be
located in the network not in the cell center. Many of network bright
XBPs were consisted of magnetically bipolar loops. (5) Ellerman bombs
By studying the fine structure of Ellerman bomb, we have found core-halo
structure and loop like fine-structures in the chromosphere. Discussions
on the origin of bombs will be given from the viewpoint of magnetic
reconnection theory.
---------------------------------------------------------
Title: Giant Chromospheric Anemone Jet Observed with Hinode and
Comparison with Magnetohydrodynamic Simulations: Evidence of
Propagating Alfvén Waves and Magnetic Reconnection
Authors: Nishizuka, N.; Shimizu, M.; Nakamura, T.; Otsuji, K.; Okamoto,
T. J.; Katsukawa, Y.; Shibata, K.
2008ApJ...683L..83N Altcode: 2008arXiv0810.3384N
Hinode discovered a beautiful giant jet with both cool and hot
components at the solar limb on 2007 February 9. Simultaneous
observations by the Hinode SOT, XRT, and TRACE 195 Å satellites
revealed that hot (~5 × 10<SUP>6</SUP> K) and cool (~10<SUP>4</SUP>
K) jets were located side by side and that the hot jet preceded the
associated cool jet (~1-2 minutes). A current-sheet-like structure
was seen in optical (Ca II H), EUV (195 Å), and soft X-ray emissions,
suggesting that magnetic reconnection is occurring in the transition
region or upper chromosphere. Alfvén waves were also observed with
Hinode SOT. These propagated along the jet at velocities of ~200
km s<SUP>-1</SUP> with amplitudes (transverse velocity) of ~5-15 km
s<SUP>-1</SUP> and a period of ~200 s. We performed two-dimensional MHD
simulation of the jets on the basis of the emerging flux-reconnection
model, by extending Yokoyama and Shibata's model. We extended the model
with a more realistic initial condition (~10<SUP>6</SUP> K corona) and
compared our model with multiwavelength observations. The improvement
of the coronal temperature and density in the simulation model allowed
for the first time the reproduction of the structure and evolution of
both the cool and hot jets quantitatively, supporting the magnetic
reconnection model. The generation and the propagation of Alfvén
waves are also reproduced self-consistently in the simulation model.
---------------------------------------------------------
Title: Cooperative Observation of Ellerman Bombs between the Solar
Optical Telescope aboard Hinode and Hida/Domeless Solar Telescope
Authors: Matsumoto, Takuma; Kitai, Reizaburo; Shibata, Kazunari;
Nagata, Shin'ichi; Otsuji, Kenichi; Nakamura, Tahei; Watanabe, Hiroko;
Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu,
Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Lites, Bruce W.;
Shine, Richard A.; Title, Alan M.
2008PASJ...60..577M Altcode:
High-resolution CaIIH broad-band filter images of NOAA10933 on 2007
January 5 were obtained by the Solar Optical Telescope aboard the Hinode
satellite. Many small-scale (∼1") bright points were observed outside
the sunspot and inside the emerging flux region. We identified some of
these bright points with Ellerman bombs (EBs) by using Hα images taken
by the Domeless Solar Telescope at Hida observatory. The sub-arcsec
structures of two EBs seen in CaIIH were studied in detail. Our
observation showed the following two aspects: (1) The CaIIH bright
points identified with EBs were associated with the bipolar magnetic
field structures, as reported by previous studies. (2)The structure
of the CaIIH bright points turned out to consist of the following two
parts: a central elongated bright core (0.7" × 0.5") located along
the magnetic neutral line and a diffuse halo (1.2"×1.8").
---------------------------------------------------------
Title: Height Dependence of Gas Flows in an Ellerman Bomb
Authors: Matsumoto, Takuma; Kitai, Reizaburo; Shibata, Kazunari;
Otsuji, Kenichi; Naruse, Takuya; Shiota, Daikou; Takasaki, Hiroyuki
2008PASJ...60...95M Altcode:
We performed spectroscopic observations of Ellerman bombs (EBs) in
an active region of NOAA 10705 at Hida Observatory on 2004 November
24. The photospheric velocity fields of EBs have for the first time
been investigated spectroscopically. From the Doppler shifts of a
TiII absorption line (6559.576Å) and a broad Hα emission line,
we derived the photospheric velocity and the lower chromospheric
velocity, respectively. The photospheric velocity of EBs was ∼
0.2kms<SUP>-1</SUP>, indicating downward flow, on average. We found
that the photospheric velocity variation of EBs has a good temporal
correlation with the Hα wing emission variation. On the other hand, the
chromospheric velocity showed an upward flow of ∼1-3kms<SUP>-1</SUP>
on the average. From the characteristics of the flow field, we
conclude that the observed EB occurred at the upper photospheric
level. We suggest that it is important to know the motions of EBs in
the photosphere because a plausible triggering mechanism of EBs is
magnetic reconnection in the low-lying atmosphere.
---------------------------------------------------------
Title: Giant chromospheric jet observed with Hinode and magnetic
reconnection model
Authors: Nishizuka, Naoto; Shimizu, Masaki; Nakamura, Tahei; Otsuji,
Kenichi; Okamoto, Takenori; Shibata, Kazunari; Katsukawa, Yukio
2008cosp...37.2239N Altcode: 2008cosp.meet.2239N
Heating of the solar chromosphere and corona is one of the long-standing
puzzles in astronomy and also a key to understand the Sun-Earth
connection through solar wind and EUV/X-ray radiation. A solar space
telescope mission Hinode revealed that solar chromosphere is much more
dynamic than had been thought and is full of tiny jets, which may be
a key to resolve the puzzle of chromospheric and coronalheating. It
has long been observed that H-alpha jets called surges often occur in
the chromosphere. They have been believed to be produced by magnetic
reconnection, which is an energy conversion mechanism from magnetic
energy into thermal and kinetic energies of plasma when anti-parallel
magnetic fields encounter and reconnect with each other. Hinode's
new chromospheric observations (with Calcium II H broad band filter)
revealed that jets are ubiquitous in the chromosphere and some of the
jets show evidence of magnetic reconnection. However, there have not
been simultaneous observations of the chromospheric jets at X-ray,
EUV, and Optical (at Calcium II H line) wavelengths until now. Here
we report first multi-wavelength observations of a chromospheric
jet with Solar Optical Telescope (SOT) and X-Ray Telescope (XRT)
on board Hinode and TRACE 195A filter. With its unprecedented high
quality instruments at both optical and X-rays, Hinode discovered a
beautiful, giant jet with both cool (104 K) and hot (5x106 K) components
at the solar limb. TRACE satellite also observed the same jet with
EUV telescope and revealed the existence of both hot (106 K) and cool
(unknown temperature) components. These data set are probably the best
multi-wavelength observations of solar jets until now. We also performed
magnetohydrodynamic simulation of the jet based on the reconnection
model and found that it can explain various observational facts very
well. It has often been argued that some of solar jets are produced by
magnetic reconnection, but previous observations had a limitation on
spatial and temporal resolutions and temperature coverage. Using these
new data and twodimensional magnetohydrodynamic simulations of the jet,
we showed, for the first time, how hot and cool jets are heated and
accelerated during the reconnection, including associated generation of
Alfvén waves. This jet formation dynamics would show a proto-tyep of
reconnection e model of solar jets and can be applied for other small
jets discovered by Hinode, which might heat the chromosphere and corona.
---------------------------------------------------------
Title: Chromospheric Anemone Jets as Evidence of Ubiquitous
Reconnection
Authors: Shibata, Kazunari; Nakamura, Tahei; Matsumoto, Takuma; Otsuji,
Kenichi; Okamoto, Takenori J.; Nishizuka, Naoto; Kawate, Tomoko;
Watanabe, Hiroko; Nagata, Shin'ichi; UeNo, Satoru; Kitai, Reizaburo;
Nozawa, Satoshi; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi;
Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Berger,
Thomas E.; Lites, Bruce W.; Shine, Richard A.; Title, Alan M.
2007Sci...318.1591S Altcode: 2008arXiv0810.3974S
The heating of the solar chromosphere and corona is a long-standing
puzzle in solar physics. Hinode observations show the ubiquitous
presence of chromospheric anemone jets outside sunspots in active
regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers
long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their
velocity is 10 to 20 kilometers per second. These small jets have an
inverted Y-shape, similar to the shape of x-ray anemone jets in the
corona. These features imply that magnetic reconnection similar to that
in the corona is occurring at a much smaller spatial scale throughout
the chromosphere and suggest that the heating of the solar chromosphere
and corona may be related to small-scale ubiquitous reconnection.
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Title: Small-Scale Magnetic-Flux Emergence Observed with Hinode
Solar Optical Telescope
Authors: Otsuji, Kenichi; Shibata, Kazunari; Kitai, Reizaburo; Ueno,
Satoru; Nagata, Shin'ichi; Matsumoto, Takuma; Nakamura, Tahei;
Watanabe, Hiroko; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto,
Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.;
Lites, Bruce; Shine, Richard A.; Title Alan M.
2007PASJ...59S.649O Altcode: 2007arXiv0709.3207O
We observed small-scale magnetic-flux emergence in a sunspot moat region
by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We
analyzed filtergram images observed at wavelengths of Fe 6302Å, G band,
and CaII H. In Stokes I images of Fe 6302Å, emerging magnetic flux was
recognized as dark lanes. In the G band, they showed to be their shapes
almost the same as in Stokes I images. These magnetic fluxes appeared
as dark filaments in CaII H images. Stokes V images of Fe 6302Å showed
pairs of opposite polarities at footpoints of each filament. These
magnetic concentrations were identified to correspond to bright points
in G band/CaII H images. From an analysis of time-sliced diagrams, we
derived the following properties of emerging flux, which are consistent
with those of previous studies: (1) Two footpoints separate each other
at a speed of 4.2kms<SUP>-1</SUP> during the initial phase of evolution,
and decrease to about 1kms<SUP>-1</SUP> 10minutes later. (2) CaII H
filaments appear almost simultaneously with the formation of dark lanes
in Stokes I in an observational cadence of 2minutes. (3) The lifetime
of the dark lanes in the Stokes I and G band is 8minutes, while that
of Ca filament is 12minutes. An interesting phenomena was observed,
that an emerging flux tube expanded laterally in the photosphere with a
speed of 3.8kms<SUP>-1</SUP>. A discussion on the horizontal expansion
of the flux tube is given with refernce to previous simulation studies.
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Title: Umbral Fine Structures in Sunspots Observed with Hinode Solar
Optical Telescope
Authors: Kitai, Reizaburo; Watanabe, Hiroko; Nakamura, Tahei; Otsuji,
Ken-ichi; Matsumoto, Takuma; UeNo, Satoru; Nagata, Shin'ichi; Shibata,
Kazunari; Muller, Richard; Ichimoto, Kiyoshi; Tsuneta, Saku; Suematsu,
Yoshinori; Katsukawa, Yukio; Shimizu, Toshifumi; Tarbell, Theodore D.;
Shine, Richard A.; Title, Alan M.; Lites, Bruce
2007PASJ...59S.585K Altcode: 2007arXiv0711.3266K
A high resolution imaging observation of a sunspot umbra was made with
the Hinode Solar Optical Telescope. Filtergrams at wavelengths of the
blue and green continua were taken during three consecutive days. The
umbra consisted of a dark core region, several diffuse components,
and numerous umbral dots. We derived basic properties of umbral dots
(UDs), especially their temperatures, lifetimes, proper motions,
spatial distribution, and morphological evolution. The brightness
of UDs is confirmed to depend on the brightness of their surrounding
background. Several UDs show fission and fusion. Thanks to the stable
condition of the space observation, we could for the first time follow
the temporal behavior of these events. The derived properties of the
internal structure of the umbra are discussed from the viewpoint of
magnetoconvection in a strong magnetic field.
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Title: Preliminary experimental results of gas recycling subsystems
except carbon dioxide concentration
Authors: Otsuji, K.; Sawada, T.; Satoh, S.; Kanda, S.; Matsumura,
H.; Kondo, S.; Otsubo, K.
1987AdSpR...7d..69O Altcode: 1987AdSpR...7...69O
Oxygen concentration and separation is an essential factor for
air recycling in a CELSS. Furthermore, if the value of the plant
assimilatory quotient is not coincident with that of the animal
respiratory quotient, the recovery of O<SUB>2</SUB> from the
concentrated CO<SUB>2</SUB> through chemical methods will become
necessary to balance the gas contents in a CELSS. Therefore,
oxygen concentration and separation equipment using Salcomine and
O<SUB>2</SUB> recovery equipment, such as Sabatier and Bosch reactors,
were experimentally developed and tested.
