| Date |
|
Name |
Title |
Abstract |
File |
| 04-12 |
long |
K. Ichimoto |
Solar Projects in 2021 |
|
pdf
10 MB |
| 04-19 |
long |
A. Asai |
|
|
MB |
| 04-26 |
main |
S. UeNo |
Investigation of long-term variation of solar CaII K intensity and Reproduction of solar UV variation
|
|
pdf
7.4 MB |
| 05-10 |
main |
S. Nagata |
Solar Magnetic Activity Research Telescope (SMART)
|
|
pdf
15 MB |
| 05-17 |
main |
K. Nishida |
Magnetic reconnection and plasmoid ejections in solar flare
|
In today's solar seminar, I will introduce my papers on MHD simulation of solar flares.
"Numerical examination of plasmoid-induced reconnection model for solar flares: the relation between plasmoid velocity and reconnection rate"
Nishida et al., ApJ 690:748 (2009)
"The role of a flux rope ejection in a three-dimensional magnetohydrodynamic simulation of a solar flare"
Nishida, Nishizuka, Shibata, ApJL, 775:L39 (2013)
"What factors determine durations of solar flares?"
Nishida, Nishizuka, Shibata (in prep)
|
pdf
27 MB |
| 05-24 |
main |
Y.A. Yamashiki |
An MHD Modeling of Successive X2.2 and X9.3 Solar Flares of 2017 September 6 |
Solar active region 12673 produced two successive X-class flares (X2.2 and X9.3) approximately 3 hours apart in September 2017. The X9.3 was the recorded largest solar flare in Solar Cycle 24. In this study we perform a data-constrained magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the initiation and dynamics of the X2.2 and X9.3 flares. According to our simulation, the X2.2 flare is first triggered by magnetic reconnection at a local site where at the photosphere the negative polarity intrudes into the opposite-polarity region. This magnetic reconnection expels the innermost field lines upward beneath which the magnetic flux rope is formed through continuous reconnection with external twisted field lines. Continuous magnetic reconnection after the X2.2 flare enhances the magnetic flux rope, which is lifted up and eventually erupts via the torus instability. This gives rise to the X9.3 flare.
|
MB |
| 05-31 |
short |
D. Yamasaki |
An MHD Modeling of Successive X2.2 and X9.3 Solar Flares of 2017 September 6 |
Solar active region 12673 produced two successive X-class flares (X2.2 and X9.3) approximately 3 hours apart in September 2017. The X9.3 was the recorded largest solar flare in Solar Cycle 24. In this study we perform a data-constrained magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the initiation and dynamics of the X2.2 and X9.3 flares. According to our simulation, the X2.2 flare is first triggered by magnetic reconnection at a local site where at the photosphere the negative polarity intrudes into the opposite-polarity region. This magnetic reconnection expels the innermost field lines upward beneath which the magnetic flux rope is formed through continuous reconnection with external twisted field lines. Continuous magnetic reconnection after the X2.2 flare enhances the magnetic flux rope, which is lifted up and eventually erupts via the torus instability. This gives rise to the X9.3 flare.
link: https://arxiv.org/pdf/2104.06639.pdf
|
pdf
4.1 MB |
|
main |
T.T. Ishii |
Introduction of SMART (Solar Magnetic Activity Research Telescope) / SDDI (Solar Dynamics Doppler Imager) Event Report and Websites for Observers |
Tommorow, I would like to introduce SMART/SDDI event report and web sites for observers.
Recent events
2021-Apr-20(JST) M-class flare at NOAA 12816.
2021-May-06(JST) Large eruption from east limb.
2021-May-23 & 24 Small flares and ejections at NOAA 12824
https://www.kwasan.kyoto-u.ac.jp/topics/kako.html
https://www.hida.kyoto-u.ac.jp/SMART/SDDI/event_report/
For checking movies, I think it is better to access the web site by your self rather than to share screen on webex.
|
pptx
19 MB |
| 06-07 |
M2 interm report |
D. Inoue |
太陽ジェット現象におけるFIP効果の研究 |
|
pptx
MB |
|
M2 interm report |
H. Shirato |
SMART/SDDIによる太陽大気における波動の伝播と磁場との関係の観測的研究 |
I will introduce my research for M2 interm report. |
pptx
MB |
| 06-14 |
short |
Y. Kotani |
Extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI |
In tomorrow's short talk, I'll introduce the following letter about campfires observed by Solar Orbiter.
"Extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI" (Berghmans et al. 2021)
https://ui.adsabs.harvard.edu/abs/2021arXiv210403382B/abstract
|
pdf
2.1 MB |
|
main |
C.P. Denis |
A fast-filament eruption observed in the H-alpha line: Imaging spectroscopy diagnostic and numerical modeling |
In this talk I will briefly summarize the observational aspects of the eruption detected by SMART/SDDI on 2017 April 23, and the application of a numerical model to interpret the observational results.
|
MB |
| 06-21 |
short |
K. Kihara |
Large Solar Energetic Particle Events Associated with Filament Eruptions Outside of Active Regions |
Today, in my short talk, I introduce following paper."Large Solar Energetic Particle Events Associated with Filament Eruptions Outside of Active Regions" Gopalswamy et al., 2015, ApJ, 806, 8
https://ui.adsabs.harvard.edu/abs/2015ApJ...806....8G/abstract
|
pdf
MB |
|
main |
H. Isobe |
NO PRESENTATION |
|
MB |
| 06-28 |
long |
T. Yokoyama |
Overview on the Researches in our group |
|
MB |
| 07-12 |
short |
D. Inoue |
The Variability of Solar Coronal Abundances in Active Regions and the Quiet Sun |
Today, in my short talk, I will introduce the following paper."The Variability of Solar Coronal Abundances in Active Regions and the Quiet Sun"(Doschek and Warren 2019)
https://ui.adsabs.harvard.edu/abs/2019ApJ...884..158D/abstract
|
pptx
MB |
|
main |
A.D. Kawamura |
Detailed Analysis of Solar Data Related to Historical Extreme Geomagnetic Storms: 1868 – 2010 |
At today's solar seminar, I will talk about my recent updates on the solar flare statistics study with a brief review of the following paper. Lefèvre+(2016) "Detailed Analysis of Solar Data Related to Historical Extreme Geomagnetic Storms: 1868 – 2010," Solar Physics 291:1483–1531.
|
MB |
| 07-19 |
short |
H. Shirato |
Vertical propagation of acoustic waves in the solar internetwork as observed by IRIS |
At today’s seminar, in my short talk, I’d like to introduce the following paper. “Vertical propagation of acoustic waves in the solar internetwork as observed by IRIS”
Kayshap et al. 2018
https://ui.adsabs.harvard.edu/abs/2018MNRAS.479.5512K/abstract
| pptx
7.4 MB |
| Date |
|
Name |
Title |
Abstract |
File |
| 10-04 |
short |
S. Nagata |
Solar Magnetic Activity Reserch Telescope (SMART):new project for flare and particle acceleration with T3 and T4 |
|
pptx
15.3 MB |
|
main |
Y.W. Huang |
SPECTRA: An Education/Research purpose Non-LTE Radiative Transfer Code |
|
pdf
959.1 KB |
| 10-11 |
short |
S. UeNo |
Bright Network, UVA, and the Physical Modeling of Solar Spectral and Total Irradiance in Recent Solar Cycles |
This paper was already published three years ago. However, Kakuwa & UeNo (2021) developed the new calibration method of converting the density of old photo-plate imaging data into the brightness. After that, we are now investigating appropriate method to reproduce long-term solar UV variation by using the converted CaII K brightness dataset. This paper shows one of good candidates of the method. On the other hand, recently, stellar physicists are trying to reproduce stellar UV time-variation by using stellar chromospheric spectral lines, such as CaII K. The information of this paper may give them some hints for understanding relationship between spectral line-profile and stellar UV radiation. Moreover, after this paper was submitted, the first author, J. Fontenla, died suddenly. So, this is the final achievement by him. Therefore, I would like to introduce this paper today.
https://ui.adsabs.harvard.edu/abs/2018ApJ...861..120F/abstract
| pdf
3.3 MB |
|
main |
D. Inoue |
FIP and i-FIP effects |
Today, in my main talk, I would like to talk about my study of the FIP effect in a Solar Jet. |
pptx
17.6 MB |
| 10-18 |
short |
T.T. Ishii |
SMART/SDDI event reports from 2021-June to 2021-Oct |
Today, I would like to show some movies from SMART/ SDDI event report (Jun-Oct 2021).
https://www.hida.kyoto-u.ac.jp/SMART/SDDI/event_report/
|
pptx
3.5 MB |
|
main |
H. Shirato |
SMART/SDDIによる太陽大気における波動の伝播と磁場との関係の観測的研究 |
In today’s main, I will talk about my research. |
pptx
6.6 MB |
| 10-25 |
short |
K. Nishida |
Launching of small-scale successive jets from calcium bright knots and formation of chromospheric anemone jets |
In today's solar seminar, I will introduce our study. |
pdf
10.5 MB |
|
main |
T. Otsu |
|
In tomorrow’s main, I will talk about my research on “The Sun as a Star”. |
MB |
| 11-01 |
short |
C.P. Denis |
A fast-filament eruption observed in the Hα line ― Imaging spectroscopy diagnostic and modeling ― |
|
pdf
10.5 MB |
|
main |
Y. Kida |
Trigger processes of Ejective Flares |
In today’s main, I will talk about my research on "Trigger processes of ejective flares".
|
pptx
34 MB |
| 11-08 |
short |
H. Isobe |
|
|
MB |
|
main |
Y. Hashimoto |
多波長観測と統計平衡コードによるプロミネンスの物理量診断 |
In tomorrow's main, I will talk about my research on spectral diagnostics of solar prominences. |
pptx
4.0 MB |
| 11-15 |
short |
Y.W. Huang |
Review:Linear Polarization of Ca I 4227A |
In this short talk, I will give a brief review on the linear polarization of Ca I line at 4227 A, one of the largest scattering polarization signals of the so-called Second Solar Spectrum.
|
pdf
2.2 MB |
|
main |
Y. Matsuda |
光球での振動によるエネルギー輸送について |
In tomorrow's main, I will talk about my research on energy transport by oscillation in the photosphere. |
pdf
2.8 MB |
| 11-22 |
short |
|
|
(November Festival)
|
MB |
|
main |
TBD |
|
(November Festival)
|
MB |
| 11-29 |
D2 interm report |
K. Kihara |
太陽高エネルギー粒子の発生・到達の機構解明に向けた研究 |
太陽高エネルギー粒子(SEP)は、太陽の突発現象に伴って発生することが知られており、特にコロナ質量放出(CME)の前面に駆動される衝撃波で加速されたと考えられるものが多く観測されている。SEPとその発生源であるCMEとのパラメータの間には様々な相関があることが知られているが、イベントごとのバリエーションも多く、明確に発生を決定づける要素はまだ解明されていない。そこで我々は、どのようなCMEがSEPを引き起こすのか？そして、発生から到達に至るまでどのようなタイムスケールを辿るのか？を解明するため、大規模な統計解析を行った。その結果、太陽から伸びる磁力線の足元付近で発生したCMEを由来とするSEPでは、粒子到達時間が短くなり、さらにCMEの放出速度と負の相関を持つことなどが分かった。
一方、扱ったイベント群の中には、粒子到達時間が統計的傾向から外れて長いイベントがあることが分かった。そこで我々は現在、これらのイベントを対象に詳細なイベント解析を行っている。これまでに、発生源となったフレア、及び付随する電波バーストの特徴に明確な違いがあることが分かった。さらに、粒子の放出時間を推定するVelocity Dispersion Analysis(VDA)を用いたところ、粒子の放出以前に不自然なギャップがあることが分かった。本発表では、これまでの研究の概要と現状、今後の研究の展開について報告する。 |
pdf
MB |
|
D2 interm report |
Y. Kotani |
Theoretical and Observational Studies of Small-Scale Magnetic Reconnection on the Sun towards a Unified Understanding of Flares |
Small-scale magnetic reconnection is frequently occurring in the solar atmosphere. The mechanism of this reconnection, and the associated behavior of the surrounding plasma, is a fundamental question in understanding the plasma in the solar and stellar atmospheres. In this talk, I will discuss the current structure of my doctoral thesis and the statistical analysis of cold plasma ejections with flares.
In the Sun and stars, observational indications of cold plasma ejections accompanied by flares are found for various spatial scales. Many common properties are found between them, regardless of their scale. However, no physical quantities such as mass have been quantitatively estimated and examined for correlations for flare energies over ten orders of magnitude until now. In this study, we statistically analyze the spectra of various scale cold plasma ejections associated with flares by performing Hα imaging spectroscopy of the solar full-disk images with SMART/SDDI. We determined the ejected mass by cloud model fitting to the Hα spectrum. We estimated flare energy by DEM analysis using SDO/AIA for small-scale flare and by estimating the bolometric energy for large-scale flare. 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 and 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 various scale cold plasma ejections with flares are caused by the same mechanism.
|
pptx
17.4 MB |
|
D2 interm report |
D. Yamasaki |
|
|
MB |
| 12-06 |
short |
A.D. Kawamura |
|
|
MB |
|
main |
TBD |
|
|
MB |
| 12-13 |
short |
TBD |
|
|
MB |
|
main |
TBD |
|
|
MB |
| 12-20 |
short |
TBD |
|
|
MB |
|
main |
TBD |
|
|
MB |
| 01-17 |
short |
TBD |
|
|
MB |
|
main |
TBD |
|
|
MB |
| 01-24 |
short |
TBD |
|
|
MB |
|
main |
TBD |
|
|
MB |