5月9日（月）13:30～15:00 太陽系小天体セミナー 南棟２階会議室
May 9 Mon Solar System Minor Body Seminar Conference Room, South Bldg.2F
5月11日（水）10:30～12:00 総研大コロキウム 中央棟（北）1F講義室
May 11 wed SOKENDAI colloquium Lecture Room
5月11日（水）13:30～14:30 理論コロキウム コスモス会館会議室
May 11 wed DTA colloquium Conference Room, Cosmos Lodge
5月13日（金）13：30～15:00 太陽天体プラズマセミナー 院生セミナー室
May 13 Fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
詳細は以下をご覧下さい。
5月9日（月）
- 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
- 5月9日（月曜日）13時30分～15時
- 場所
- 南棟２階会議室
- 講演者
- 有松亘
- 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
5月11日（水）
- Campus
- Mitaka
Seminar Name : SOKENDAI colloquium
Regular / Irregular : Regular
Date：10:30-12:00, May 11, 2016 - Place
- Lecture Room
Speaker 1: Tsuguru Ryu - Affiliation
- SOKENDAI, (supervisor : Saeko Hayashi)
- Title
- Direct imaging observations of intermediate mass giants with RV trends II
Speaker 2：Hisakazu Uchiyama - Affiliation
- D2, SOKENDAI, Mitaka（supervisor : Nobunari Kashikawa）
- Title
- Correlation between protoclusters and QSOs using HSC
Organizer
Name : Kotomi Taniguchi
TV conference system is available connecting from Nobeyama, Hawaii,
Mizusawa, and Okayama.
5月11日（水）
- Campus
- Mitaka
- Seminar
- DTA colloquium
- Regularly Scheduled/Sporadic
- Regularly Scheduled Date and time：11 May 2016, 13:30-14:30
- Place
- Conference Room, Cosmos Lodge
- Speaker
- Masahiro Ogihara
- Affiliation
- NAOJ DTA
- Title
- Formation of close-in super-Earths
- Abstract
- Recent observations of exoplanets have revealed a large number of close-in low-mass planets (or close-in super-Earths). As of April 2016, 351 systems harbor 877 close-in super-Earths. We can discuss the origin of these planets by comparing observed orbital distributions with results of numerical simulations of planet formation. In this talk, I will introduce our recent papers on formation of close-in super-Earths (Ogihara et al. 2015, A&A, 578; Ogihara et al. 2015, A&AL, 584). I will also show some preliminary results of ongoing projects.
- Facilitator
- -Name：Tomoya Takiwaki
- Comment
- in English
5月13日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 13 May (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Munehito Shoda
- Affiliation
- The University of Tokyo
- Title
- Generation of upward Alfvenic waves by the chromospheric shock waves
- Abstract
-
Classically, the solar chromosphere was thought to be a dissipative medium for Alfven waves, in that those generated by the convective motions were thought to dissipate most of their energy there. However, recent high-resolution observations near the coronal base strongly suggest that the upward Alfven waves are generated or amplified in the chromosphere by the large amplitude acoustic (shock) waves. This means that the classical wave-turbulence modelings of the solar corona and the solar wind need some modification, because most of such modelings neglect the interaction between the acoustic waves and the Alfven waves.
Understanding the Alfven wave generation in the solar chromosphere is essential for more realistic modeling.
We have performed both numerical simulations of one-dimensional MHD systems and the observations of the transverse Doppler velocities using off-limb spicule observation by IRIS. We first have investigated numerically the nonlinear interaction between large-amplitude acoustic
(shock) waves and small-amplitude Alfven waves in the chromosphere. We have found that, if the plasma beta is around unity, Alfven waves are trapped and amplified around the shock front, leading to the strong amplification of the Alfven waves. From this process, only upward Alfven waves are generated. Since this process is likely to occur for strong acoustic shock waves propagating in a beta-unity plasma, the solar chromosphere is a favorable place for this process.
We have compared the power-spectrum of the transverse velocity between the simulations and observations. Mg II k line is used for deriving the observational transverse velocities in the chromosphere. The similarity of the power spectrum strongly suggests that the generation of upward Alfvenic waves occur in the middle chromosphere under the formation height of Mg II k line. - Facilitator
- -Name：Shin Toriumi
- Comment