12月3日（火）13:30～15:00 太陽系小天体セミナー 南棟２階会議室
Dec 3 Tue Solar System Minor Body Seminar Conference Room, South Bldg.2F
12月3日（火）13:30～15:00 太陽天体プラズマセミナー すばる棟院生セミナー室
Dec 3 Tue Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
12月4日（水）10:30 -12:00 総研大コロキウム 講義室
Dec 4 Wed SOKENDAI colloquium Lecture Room
12月6日（金）13:30～15:00 太陽天体プラズマセミナー すばる棟院生セミナー室
Dec 6 Fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
詳細は以下をご覧下さい。
12月3日（火）
- キャンパス
- 三鷹
- セミナー名
- 太陽系小天体セミナー
- 定例・臨時の別
- 定例
- 日時
- 12月3日（火曜日）13時30分～15時
- 場所
- 南棟２階会議室
- 連絡先
- 名前：渡部潤一
- 備考
- テレビ会議またはスカイプによる参加も可
12月3日（火）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 03 December (Tue), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Abraham Chian
- Affiliation
- National Institute for Space Research (INPE), Brazil
- Title
- Nonlinear Dynamics of solar-interplanetary plasmas
- Abstract
- Solar-interplanetary plasmas are governed by nonlinear dynamical phenomena such as vortex, magnetic flux rope, magnetic reconnection, and intermittent turbulence. In this seminar I will give an overview of some recent theoretical and observational studies of coherent structures, magnetic reconnection, and turbulence. First, we discuss the detection of Lagrangian coherent structures in numerical simulation of turbulent dynamos and Hinode observation of photospheric turbulence. Second, we present the simultaneous ground and space observations of an erupting coronal loop which show that type-II solar radio bursts can be emitted from both upstream and downstream of the shock wave front. Third, we present the observational evidence of magnetically reconnected current sheets in the vicinity of a turbulent front magnetic cloud boundary layer, and discuss the relation between current sheets, turbulence, and magnetic reconnections at the leading edge of an interplanetary coronal mass ejection. Finally, we report the observation of magnetic reconnection at the interface region of two interplanetary magnetic flux ropes. The front and rear boundary layers of three interplanetary magnetic flux ropes are identified by in situ spacecraft measurements. A quantitative analysis of the reconnection condition and the degree of intermittency reveals that rope-rope magnetic reconnection is the most likely site for genesis of interplanetary intermittent turbulence in this event. The dynamic pressure pulse resulting from this reconnection triggers the onset of a geomagnetic storm.
- Facilitator
- -Name：Munehito Shoda
12月4日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- December 4th, 2019, 10:30 -12:00
- Place
- Lecture Room
- Speaker
- Noriharu Watanabe
- Affiliation
- SOKENDAI 4th year (D2) (Supervisor: Norio Narita, Hideki Takami, Wako Aoki)
- Title
- TBD
- Speaker
- Takaharu Sisido
- Affiliation
- SOKENDAI 3rd year (D1) (Supervisor: Takayuki Tomaru, Yoichi Aso, Ryutaro Takahashi)
- Title
- the thermal conductivity measurement for sapphire and Si fiber
- Facilitator
- -Name： Kei Ito
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 06 December (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Takafumi Kaneko
- Affiliation
- Nagoya University
- Title
- Numerical study on internal velocity field variation of eruptive solar prominence
- Abstract
-
Solar prominences are cool dense plasma clouds in the hot tenuous corona. They sometimes erupt and evolve into coronal mass ejections. Revealing the origin of cool dense plasmas and the impact on the eruptive mechanisms has been a long term issue in solar physics. Moreover, there is an increasing interest in the predictability of solar eruptions for modern space weather forecast.
It is known that the interiors of prominences are filled with turbulent flows. Recent observational studies using SMART/SDDI (Hida Obs.) reported that the standard deviation of the Doppler velocity in the eruptive prominences started to increase before eruptions even when the mean velocity was unchanged. This finding is useful to predict prominence eruptions: however, the origin of velocity field variation in the prominences and the relationship with the magnetically-driven eruptive mechanisms. In this study, we performed three-dimensional MHD simulation including gravity, optically thin radiative cooling, and nonlinear anisotropic thermal conduction, and reproduced eruption of a turbulent prominence. In our simulation, the cool dense prominence was formed by radiative condensation (thermal instability), and the prominence erupted after exceeding the critical height of torus instability. Before eruption, the velocity field inside the prominence had complicated distribution containing both upflows and downflows associated with the Kelvin-Helmholtz instability (KHI). We confirmed that the vertical velocity created increasing standard deviation, which was quantitatively consistent with the observation. We discuss how the nonlinear growth of the KHI contributes to the slow-rise until reaching the critical height of torus instability. - Facilitator
- -Name：Munehito Shoda