Dept. of Spacecraft Engineering

高島 健

タカシマ タケシ  (Takeshi Takashima)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 教授
学位
理学博士(1998年3月 早稲田大学)

J-GLOBAL ID
200901062235719944
researchmap会員ID
1000320874

論文

 153
  • Vladimir Borisovich Belakhovsky, Vyacheslav A. Pilipenko, Elizaveta E. Antonova, Yoshizumi Miyoshi, Yoshiya Kasahara, Satoshi Kasahara, Nana Higashio, Iku Shinohara, Tomoaki Hori, Shoya Matsuda, Shoichiro Yokota, Takeshi Takashima, Mitani Takefumi, Kunihiro Keika, Satoko Nakamura
    Earth, Planets and Space 75(1) 2023年12月21日  
    Abstract Variations of relativistic electron fluxes (E ≥ 1 MeV) and wave activity in the Earth magnetosphere are studied to determine the contribution of different acceleration mechanisms of the outer radiation belt electrons: ULF mechanism, VLF mechanism, and adiabatic acceleration. The electron fluxes were measured by Arase satellite and geostationary GOES satellites. The ULF power index is used to characterize the magnetospheric wave activity in the Pc5 range. To characterize the VLF wave activity in the magnetosphere, we use data from PWE instrument of Arase satellite. We consider some of the most powerful magnetic storms during the Arase era: May 27–29, 2017; September 7–10, 2017; and August 25–28, 2018. Also, non-storm intervals with a high solar wind speed before and after these storms for comparison are analyzed. Magnitudes of relativistic electron fluxes during these magnetic storms are found to be greater than that during non-storm intervals with high solar wind streams. During magnetic storms, the flux intensity maximum shifts to lower L-shells compared to intervals without magnetic storms. For the considered events, the substorm activity, as characterized by AE index, is found to be a necessary condition for the increase of relativistic electron fluxes, whereas a high solar wind speed alone is not sufficient for the relativistic electron growth. The enhancement of relativistic electron fluxes by 1.5–2 orders of magnitude is observed 1–3 days after the growth of the ULF index and VLF emission power. The growth of VLF and ULF wave powers coincides with the growth of substorm activity and occurs approximately at the same time. Both mechanisms operate at the first phase of electron acceleration. At the second phase of electron acceleration, the mechanism associated with the injection of electrons into the region of the magnetic field weakened by the ring current and their subsequent betatron acceleration during the magnetic field restoration can work effectively. Graphical Abstract
  • Hiroyuki TOYOTA, Takeshi TAKASHIMA, Hiroshi IMAMURA, Kazutaka NISHIYAMA, Takayuki YAMAMOTO, Takeshi MIYABARA, Masayuki OHTA, Yoshitaka MOCHIHARA, Naoya OZAKI, Hiroyuki NAGAMATSU, Takakazu OKAHASHI, Junko TAKAHASHI, Toshiaki OKUDAIRA, Takayuki HIRAI, Masanori KOBAYASHI, Ko ISHIBASHI, Peng HONG, Osamu OKUDAIRA, Tomoko ARAI
    Journal of Evolving Space Activities 1 2023年12月  査読有り
  • Yoshizumi Miyoshi, Yuto Katoh, Shinji Saito, Takefumi Mitani, Takeshi Takashima
    Solar-Terrestrial Environmental Prediction 115-137 2023年2月1日  
  • Hiroki Hihara, Shinpei Kondo, Mitsuhisa Yamaji, Kuniyuki Omagari, Tadateru Takahashi, Naoki Yoshizawa, Kazuyo Mizushima, Takeshi Takashima
    Infrared Remote Sensing and Instrumentation XXX 2022年9月30日  
  • Afroditi Nasi, Christos Katsavrias, Ioannis A. Daglis, Ingmar Sandberg, Sigiava Aminalragia-Giamini, Wen Li, Yoshizumi Miyoshi, Hugh Evans, Takefumi Mitani, Ayako Matsuoka, Iku Shinohara, Takeshi Takashima, Tomoaki Hori, Georgios Balasis
    FRONTIERS IN ASTRONOMY AND SPACE SCIENCES 9 2022年8月  
    During July to October of 2019, a sequence of isolated Corotating Interaction Regions (CIRs) impacted the magnetosphere, for four consecutive solar rotations, without any interposed Interplanetary Coronal Mass Ejections. Even though the series of CIRs resulted in relatively weak geomagnetic storms, the net effect of the outer radiation belt during each disturbance was different, depending on the electron energy. During the August-September CIR group, significant multi-MeV electron enhancements occurred, up to ultra-relativistic energies of 9.9 MeV in the heart of the outer Van Allen radiation belt. These characteristics deemed this time period a fine case for studying the different electron acceleration mechanisms. In order to do this, we exploited coordinated data from the Van Allen Probes, the Time History of Events and Macroscale Interactions during Substorms Mission (THEMIS), Arase and Galileo satellites, covering seed, relativistic and ultra-relativistic electron populations, investigating their Phase Space Density (PSD) profile dependence on the values of the second adiabatic invariant K, ranging from near-equatorial to off equatorial mirroring populations. Our results indicate that different acceleration mechanisms took place for different electron energies. The PSD profiles were dependent not only on the mu value, but also on the K value, with higher K values corresponding to more pronounced local acceleration by chorus waves. The 9.9 MeV electrons were enhanced prior to the 7.7 MeV, indicating that different mechanisms took effect on different populations. Finally, all ultra-relativistic enhancements took place below geosynchronous orbit, emphasizing the need for more Medium Earth Orbit (MEO) missions.

MISC

 174
  • 徳留真一郎, 餅原義孝, 三浦政司, 坂本勇樹, 森下直樹, 山本高行, 荒川聡, 竹内伸介, 竹前俊昭, 豊田裕之, 奥平俊暁, 太刀川純孝, 寺島啓太, 紙田徹, 今村裕志, 高島健
    宇宙科学技術連合講演会講演集(CD-ROM) 67th 2023年  
  • 秋月祐樹, 澤田健一郎, 金城富宏, 小川博之, 西山和孝, 豊田博之, 今村裕志, 高島健
    宇宙科学技術連合講演会講演集(CD-ROM) 67th 2023年  
  • 須崎祐多, HONG Peng K., 石橋高, 宮原剛, 太田方之, 細沼貴之, 尾崎直哉, 豊田裕之, 西山和孝, 大槻真嗣, 奥平修, 佐藤峻介, 高島健, 豊永洸大, 藤島早織, 萩原啓司
    宇宙科学技術連合講演会講演集(CD-ROM) 67th 2023年  
  • 荒井朋子, 小林正規, 石橋高, 木村宏, 平井隆之, 岡本尚也, 山田学, 吉田二美, 吉田二美, 秋田谷洋, 千秋博紀, 和田浩二, SRAMA Ralf, HARALD Krueger, MARSHALL Sean, MARSHALL Sean, 佐々木晶, 薮田ひかる, 石黒正晃, 関口朋彦, 浦川聖太郎, 渡部潤一, 伊藤孝士, 大坪貴文, 大塚勝仁, 阿部新助, 中村智樹, 廣井孝弘, 諸田智克, 紅山仁, 橘省吾, 三河内岳, 野口高明, 中村メッセンジャー圭子, 小松睦美, 金田英宏, 小松吾郎, 小松吾郎, 出村裕英, 平田成, 伊藤元雄, 山口亮, 松浦周二, 巽瑛理, 柳沢俊史, 黒崎裕久, 矢野創, 吉川真, 尾崎直哉, 山本高行, 豊田裕之, 西山和孝, 今村裕志, 高島健
    宇宙科学技術連合講演会講演集(CD-ROM) 67th 2023年  
  • 三浦政司, 餅原義孝, 徳留真一郎, 荒川聡, 竹前俊昭, 森下直樹, 山本高行, 太刀川純孝, 竹内伸介, 豊田裕之, 奥平俊暁, 坂本勇樹, 寺島啓太, 紙田徹, 高島健
    宇宙科学技術連合講演会講演集(CD-ROM) 66th 2022年  

共同研究・競争的資金等の研究課題

 25