| Date |
|
Name |
Title |
Abstract |
File |
| 4/13 |
|
Asai |
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| 4/20 |
|
Denis |
Acceleration process of a solar filament eruption: observation and numerical modeling |
In this talk, I will explore the dynamics and acceleration process of a fast-filament eruption by combining imaging spectroscopy observations and numerical modeling.
By adapting the toroidal current loop equations within the context of the torus instability, we modeled the evolution of the filament eruption and solved the equation of motion for different scenarios involving full and partial toroidal flux rope configurations.
We demonstrate that the eruption process of the filament can be equally described by models based on either the conservation of magnetic flux or conservation of total energy, with the added constraint that the electric current accounting for the free magnetic energy is restricted to the expanding flux rope above the photosphere.
However, neither model independently satisfies the conservation of energy and magnetic flux simultaneously.
We propose a novel composite model that incorporates a non-constant aspect ratio for the toroidal flux rope.
This composite model not only maintains consistency with the conservation laws but also yields a remarkable fit to the observational data, thus offering a more comprehensive representation of the eruption process.
Furthermore, by incorporating the mass-loss effect in our simulations, we successfully reproduced the fast component of the eruption. This confirms that mass loss, manifesting as draining material or downflows, directly modulates the acceleration phase of the filament.
Based on the results of our best-fitting model, we also quantified the energy budget of the high-speed eruption.
Additionally, the role of the driving forces in the evolution of the toroidal flux rope is also investigated.
|
pdf
19.2 MB
|
| 4/27 |
|
Ishii |
|
Today, I would like to introduce some websites for space weather.
https://www.kwasan.kyoto-u.ac.jp/~ishii/webpage_list.html
|
|
| 5/11 |
|
Dai |
Pre-eruptive Longitudinal Oscillations of a Kink-unstable Filament Observed by CHASE and SMART |
The current work focuses on the pre-eruptive evolution of a filament, including its longitudinal oscillation, Doppler velocity structures, and the possible connection with increasing twist and flux-rope instability.
Based on the current analysis, we suggest that the filament eruption was likely triggered by kink instability, and that the event eventually developed into a failed eruption.
In addition, the longitudinal oscillation before the eruption shows a strongly damped feature, which may be related to the magnetic-field evolution during the pre-eruptive phase.
Since the analysis is still ongoing, this presentation will mainly summarize the current progress and preliminary interpretation.
I would greatly appreciate your comments and suggestions on the observational evidence, physical scenario, and possible next steps.
|
pdf
3.4 MB
|
| 5/18 |
|
Ueno |
Wide-Field Spectro-Polarimeter and researches on filament magnetic fields |
At Hida Observatory, we are currently developing a wide-field spectro-polarimetric observation system for the Domeless Solar Telescope.
This system consists of two instruments: the Wide-Field Spectro-Polarimeter (WFSP) and the Ground Layer Adaptive Optics (GLAO).
Regarding the WFSP, necessary components were gradually acquired using various funding sources between 2023 and 2025, and the instrument itself is now operational and capable of acquiring observational data.
As for the GLAO, we will continue to conduct fundamental experiments in collaboration with Kitami Institute of Technology in this year also.
In this Solar Seminar, I will first discuss observational researches on filaments and prominences as one of key scientific objectives of this system, and present on WFSP's specific configuration, features and examples of observational data.
|
pdf
6.4 MB
|
| 5/25 |
|
Shirato |
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| 6/1 |
|
Natsume |
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| 6/8 |
|
Yoshihisa |
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| 6/22 |
Guest Seminar |
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| 6/29 |
|
Ichihara |
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| 7/6 |
|
Fukuchi |
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| 7/13 |
|
Umezawa |
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