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2016.5.9-5.15

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

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