PPARC seminar news #17 in FY2018


2018/11/12 (Mon.) 9:00-12:00 @ Science Complex C S407

Chairperson: Koga


Hiroaki Misawa 三澤浩昭 (Associate professor)

   Review: Characteristics of solar radio bursts relating to energetic particle events

   It is known that the sun radiates highly energetic particles in association with its short-term variation such as flare and coronal mass ejection, which are called solar energetic particles (SEPs). In the maximum flux case, the SEP flux is estimated to be approximately 1Sv at the altitude of space-station, therefore the early stage forecast for the occurrence 'timing' and 'magnitude' of SEPs are one of the most important research subjects of space-weather and space-disaster. SEPs are often accompanied with solar radio bursts (SRBs), so it is expected to make early stage warning for SEPs by detecting SRBs. In this seminar, I would like to report characteristics of SRBs relating to SEPs from the view point of early stage warning of SEPs, and discuss future studies of SRBs for upcoming solar minimum activity phase when occurrence of SEPs and SRBs is also known to be inactive. 

Fuminori Tsuchiya 土屋史紀 (Assistant professor)

   Azimuthal variation in the Io plasma torus observed by the Hisaki satellite (Arakawa M-thesis follow up)

  The inner area of a planetary magnetosphere generally contains a dense plasma region that corotates with the planet. In the Jovian magnetosphere, sulfur and oxygen ions supplied by the satellite Io are distributed in what is called the Io plasma torus. Various plasma parameters in the torus have significant azimuthal variations that are coupled with the energy flows in the Jovian inner magnetosphere. In this study, 3 years of data obtained by the Hisaki satellite, from December 2013 to August 2016, were used to investigate the azimuthal variations and to find how the variations were influenced by the increase in neutral particles from Io. The azimuthal variation was obtained from a time series of sulfur ion line ratios, which were sensitive to the electron temperature and the sulfur ion mixing ratio S3+/S+. The major characteristics of the azimuthal variation in the plasma parameters were consistent with the dual hot electron model, proposed to explain previous observations. On the other hand, the Hisaki data showed that the peak System III longitude in the S3+/S+ ratio was located not only around 0-45deg, as in previous observations, but also around ~180deg. The rotation period, the so-called System IV periodicity, was sometimes close to the Jovian rotation period. A persistent input of energy to electrons in a limited longitude range of the torus is associated with the shortening of the System IV period.

- 10/19鈴木<=>12/3笠羽 の発表入替
----- PPARC seminar schedule (v1.7, 2018-11-06) ---
18/10/22(Mon) B4研究発表会
18/10/29(Mon) 9:00-12:00 Koga (Yagi)
18/11/05(Mon) 9:00-12:00 Yagi, Obara (Suzuki)
18/11/08(Thu)  地物合同セミナー
18/11/12(Mon) 9:00-12:00 Tsuchiya, Misawa (Koga)
18/11/19(Mon) 9:00-12:00 Kasaba, Sakanoi (Hirai)
18/11/23-27 SGEPSS
18/12/03(Mon) 9:00-12:00 Kagitani, Suzuki (Watanabe)
18/12/10(Mon) 9:00-12:00 an optional day
18/12/17(Mon) 9:00-12:00 an optional day
18/12/24(Mon) holiday
19/01/07(Mon) 9:00-12:00 Oura, Yamaguchi, Kanbara (Fukizawa)
19/01/08(Tue) 13:00-14:00 Fujimoto (Ooura)
19/01/14(Mon) holiday
19/01/15(Tue) B4研究発表会
19/01/21(Mon) Yagi, Suzuki (Kanbara)
19/01/25(Fri) M論締切
19/01/29(Tue) Watanabe, Ishikawa (Fujiomoto)
19/01/30(Wed) Fukizawa, Hirai (Yamaguchi)
19/02/04-02/08 D/M審査会
19/02/11(Mon) holiday
19/02/18-2/21 惑星圏研究会
----- 発表者 -----
D/1回: Koga
M2/1回: Ishikawa, Hirai, Fukizawa, Watanabe
M1/2回: Yagi, Suzuki, うち1回はreview
B4/2回: Oura, Kanbara, Fujimoto, Yamaguchi

----- C-group seminar schedule (v1.4, 2018-10-16) ---
18/10/25(Thu) 13:00-16:30 M thesis preliminary oral exam. (Takenaka, Toyooka)
18/11/01(Thu) 13:00-16:30 M thesis preliminary oral exam. (Hirai, Fukisawa) 
18/11/08(Thu) Chibutsu joint seminar
18/11/15(Thu) SGEPSS rehersal
18/11/23-27 SGEPSS(Nagoya)
18/11/29(Thu) 13:00- D2 interim report (koga)
18/12/13(Thu) 13:00- D2 interim report (takami)