2025/11/20 更新

写真a

キタ　ハジメ
北　元
Kita Hajime
所属
工学部 情報通信工学課程 講師
外部リンク

学位

  • 博士(理学) （ 2015年3月   東北大学 ）

研究キーワード

  • 電波干渉計

  • 放射線帯

  • 電波望遠鏡

  • 赤外望遠鏡

  • 木星

研究分野

  • 自然科学一般 / 宇宙惑星科学

論文

  • Results from Hisaki and prospects for LAPYUTA observations of the Jupiter System

    Fuminori Tsuchiya, Go Murakami, Atsushi Yamazaki, Kazuo Yoshioka, Masato Kagitani, Tomoki Kimura, Chihiro Tao, Ryoichi Koga, Hajime Kita, Jun Kimura, Shuya Tan, Kei Masunaga, Shotaro Sakai, Mizuki Yoneda, Masaki Kuwabara, Shingo Kameda, Ichiro Yoshikawa

    2025年3月

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    出版者・発行元：Copernicus GmbH  

    Remote sensing with ultraviolet wavelength (UV) are one of powerful probes to uncover dynamic behaviors of the planetary environment. The Hisaki satellite was an earth orbiting extreme ultraviolet (EUV) spectroscope dedicated for observing solar system planets. Thanks to its long-term monitoring capability, Hisaki had carried out unprecedented continuous observation of Io plasma torus, Jovian aurora, and Mars and Venus upper atmospheres from 2013 to 2023. One of notable phenomena observed by Hisaki is significant enhancements of neutral gas from presumed activation of volcanic activity on Io. Hisaki revealed, for the first time, that not only the plasma source, but transport, heating, and loss processes of magnetospheric plasma were influenced by the variation in the neutral source input.After the end of the Hisaki mission, we have proposed the next UV space telescope, LAPYUTA (Life-environmentology, Astronomy, and PlanetarY Ultraviolet Telescope Assembly). One of goals of this mission is dynamics of our solar system planets and moons as the most quantifiable archetypes of extraterrestrial habitable environments in the universe. LAPYUTA will not only provide a UV monitoring platform like Hisaki but also have a high spatial resolution and high sensitivity to uncover stability of Io’s atmosphere, water plumes that gushes from the subsurface ocean of icy moons, and spatio-temporal aspects of Jupiter's giant UV aurora. Primary goal of the LAPYUTA mission other than the Jovian system includes atmospheric evolution of Venus and Mars, characterization of exoplanet atmosphere, galaxy formation, and time-domain astronomy.

    DOI： 10.5194/egusphere-egu25-14544

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  • Solar wind response of the dawn-dusk asymmetry in the Io plasma torus using the Haleakala T60 and HISAKI satellite observations

    Hiroyasu Kondo, Fuminori Tsuchiya, Masato Kagitani, Shinnosuke Satoh, Hiroaki Misawa, Yuki Nakamura, Go Murakami, Tomoki Kimura, Atsushi Yamazaki, Ichiro Yoshikawa, Hajime Kita, Chihiro Tao

    2024年5月

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  • A search for auroral radio emission from β Pictoris b

    Yuta Shiohira, Yuka Fujii, Hajime Kita, Tomoki Kimura, Yuka Terada, Keitaro Takahashi

    Monthly Notices of the Royal Astronomical Society   528 ( 2 )   2136 - 2144   2024年2月

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    掲載種別：研究論文（学術雑誌）  

    DOI： 10.1093/mnras/stad3990

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  • Simulation of Dawn‐To‐Dusk Electric Field in the Jovian Inner Magnetosphere via Region 2‐Like Field‐Aligned Current 査読

    Yuki Nakamura, Koichiro Terada, Chihiro Tao, Naoki Terada, Yasumasa Kasaba, François Leblanc, Hajime Kita, Aoi Nakamizo, Akimasa Yoshikawa, Shinichi Ohtani, Fuminori Tsuchiya, Masato Kagitani, Takeshi Sakanoi, Go Murakami, Kazuo Yoshioka, Tomoki Kimura, Atsushi Yamazaki, Ichiro Yoshikawa

    Journal of Geophysical Research: Space Physics   128 ( 6 )   2023年6月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

    DOI： 10.1029/2022ja031248

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  • Major results from the Hisaki mission and future perspectives

    Fuminori Tsuchiya, Yasumasa Kasaba, Ichiro Yoshikawa, Go Murakami, Atsushi Yamazaki, Kazuo Yoshioka, Tomoki Kimura, Chihiro Tao, Ryoichi Koga, Hajime Kita, Kei Masunaga, Masato Kagitani, Shotaro Sakai, Masaki Kuwabara

    2023年2月

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  • Effect of Meteoric Ions on Ionospheric Conductance at Jupiter

    Yuki Nakamura, Koichiro Terada, Chihiro Tao, Naoki Terada, Yasumasa Kasaba, François Leblanc, Hajime Kita, Aoi Nakamizo, Akimasa Yoshikawa, Shinichi Ohtani, Fuminori Tsuchiya, Masato Kagitani, Takeshi Sakanoi, Go Murakami, Kazuo Yoshioka, Tomoki Kimura, Atsushi Yamazaki, Ichiro Yoshikawa

    Journal of Geophysical Research: Space Physics   127 ( 3 )   2022年3月

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    掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

    DOI： 10.1029/2022ja030312

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    その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2022JA030312

  • Jupiter's X-ray aurora during UV dawn storms and injections as observed by XMM-Newton, Hubble, and Hisaki

    A. D. Wibisono, G. Branduardi-Raymont, W. R. Dunn, T. Kimura, A. J. Coates, D. Grodent, Z. H. Yao, H. Kita, P. Rodriguez, G. R. Gladstone, B. Bonfond, R. P. Haythornthwaite

    Monthly Notices of the Royal Astronomical Society   507 ( 1 )   1216 - 1228   2021年10月

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    掲載種別：研究論文（学術雑誌）  

    DOI： 10.1093/mnras/stab2218

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  • Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 4. Quasi‐Periodic Variation

    Chihiro Tao, Tomoki Kimura, Elena A. Kronberg, Fuminori Tsuchiya, Go Murakami, Atsushi Yamazaki, Marissa F. Vogt, Bertrand Bonfond, Kazuo Yoshioka, Ichiro Yoshikawa, Yasumasa Kasaba, Hajime Kita, Shogo Okamoto

    Journal of Geophysical Research: Space Physics   126 ( 2 )   2021年2月

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    掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

    DOI： 10.1029/2020ja028575

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    その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2020JA028575

  • Long‐Term Monitoring of Energetic Protons at the Bottom of Earth’s Radiation Belt

    K. Yoshioka, Y. Miyoshi, S. Kurita, M. Teramoto, F. Tsuchiya, A. Yamazaki, G. Murakami, T. Kimura, H. Kita, I. Yoshikawa, Y. Kasaba

    Space Weather   19 ( 1 )   2021年1月

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    掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

    DOI： 10.1029/2020sw002611

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    その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2020SW002611

  • The Formation of Saturn’s and Jupiter’s Electron Radiation Belts by Magnetospheric Electric Fields

    Yi-Xin Hao, Yi-Xin Sun, Elias Roussos, Ying Liu, Peter Kollmann, Chong-Jing Yuan, Norbert Krupp, Chris Paranicas, Xu-Zhi Zhou, Go Murakami, Hajime Kita, Qiu-Gang Zong

    The Astrophysical Journal   905 ( 1 )   L10 - L10   2020年12月

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    掲載種別：研究論文（学術雑誌）   出版者・発行元：American Astronomical Society  

    DOI： 10.3847/2041-8213/abca3f

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    その他リンク： https://iopscience.iop.org/article/10.3847/2041-8213/abca3f

  • An attempt to detect transient changes in Io’s SO2 and NaCl atmosphere

    Lorenz Roth, Jeremie Boissier, Arielle Moullet, Álvaro Sánchez-Monge, Katherine de Kleer, Mizuki Yoneda, Reina Hikida, Hajime Kita, Fuminori Tsuchiya, Aljona Blöcker, G. Randall Gladstone, Denis Grodent, Nickolay Ivchenko, Emmanuel Lellouch, Kurt D. Retherford, Joachim Saur, Peter Schilke, Darrell Strobel, Sven Thorwirth

    Icarus   350   113925 - 113925   2020年11月

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    掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

    DOI： 10.1016/j.icarus.2020.113925

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  • Spatially Asymmetric Increase in Hot Electron Fraction in the Io Plasma Torus During Volcanically Active Period Revealed by Observations by Hisaki/EXCEED From November 2014 to May 2015 査読

    R. Hikida, K. Yoshioka, F. Tsuchiya, M. Kagitani, T. Kimura, F. Bagenal, N. Schneider, G. Murakami, A. Yamazaki, H. Kita, E. Nerney, I. Yoshikawa

    Journal of Geophysical Research: Space Physics   2020年3月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1029/2019ja027100

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  • Jovian UV Aurora's Response to the Solar Wind: Hisaki EXCEED and Juno Observations 査読

    H. Kita, T. Kimura, C. Tao, F. Tsuchiya, G. Murakami, A. Yamazaki, K. Yoshioka, R.W. Ebert, R.J. Wilson, F. Allegrini, G. Clark, J. E. P. Connerney, G. R. Gladstone, I. Yoshikawa, M. Fujimoto

    Journal of Geophysical Research: Space Physics   2019年12月

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    担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1029/2019ja026997

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  • Short-term Variation in the Dawn–Dusk Asymmetry of the Jovian Radiation Belt Obtained from GMRT and Hisaki EXCEED Observations 査読

    H. Kita, H. Misawa, A. Bhardwaj, F. Tsuchiya, G. Murakami, C. Tao, T. Kimura, K. Yoshioka, A. Yamazaki, Y. Kasaba, I. Yoshikawa, M. Fujimoto

    The Astrophysical Journal   2019年2月

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    掲載種別：研究論文（学術雑誌）  

    DOI： 10.3847/2041-8213/ab0427

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  • Two-element radio interferometer for the observation of Jupiter's synchrotron radiation 査読

    Fuminori Tsuchiya, Hiroaki Misawa, Hajime Kita, Akira Morioka, Tetsuro Kondo

    Proceedings of the International Symposium on Planetary Science 2011   47 - 58   2019年

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

    DOI： 10.5047/pisps.047

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  • Development of ground pipeline system for high-level scientific data products of the Hisaki satellite mission and its application to planetary space weather 査読

    Tomoki Kimura, Atsushi Yamazaki, Kazuo Yoshioka, Go Murakami, Fuminori Tsuchiya, Hajime Kita, Chihiro Tao, Ichiro Yoshikawa, Atsushi Kumamoto, Chisato Yamauchi

    Journal of Space Weather and Space Climate   2019年

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    掲載種別：研究論文（学術雑誌）  

    <jats:p>The Hisaki satellite is the first-ever space telescope mission dedicated to planetary sciences. Atmospheres and magnetospheres of our solar system planets are continuously monitored by the extreme ultraviolet (EUV) spectrometer onboard Hisaki. This paper describes a data pipeline system developed for processing high-level scientific and ancillary data products from the Hisaki mission. The telemetry data downlinked from the satellite are stored in a ground telemetry database, processed in the pipeline to imaging spectral data with a 1-min temporal resolution and ancillary data products, and then archived in a public database. The imaging spectra can be further reduced to higher-level data products for practical scientific use. For example, light curves of the power emitted from Jupiter’s aurora and plasma torus with a temporal resolution of 10-min can be reduced from the imaging spectral data; the reduced light curves reveal the transport processes of energy and mass in Jupiter’s magnetosphere and associated interplanetary solar wind conditions. Continuous monitoring with Hisaki will contribute considerably to our understanding of space weather relating to planets in our solar system.</jats:p>

    DOI： 10.1051/swsc/2019005

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  • Impact of Io's volcanic activity to environment and dynamics in the Jovian magnetosphere : from HISAKI results

    Tsuchiya, F, K. Yoshioka, T. Kimura, G. Murakami, A. Yamazaki, M. Kagitani, C. Tao, H. Kita, R. Koga, F. Suzuki, R. Hikida, Y. Kasaba, H. Misawa, T. Sakanoi, I. Yoshikawa

    Proceedings of Symposium on Planetary Science 2019   2019年

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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  • Pulsation Characteristics of Jovian Infrared Northern Aurora Observed by the Subaru IRCS with Adaptive Optics 査読

    H. Watanabe, H. Kita, C. Tao, M. Kagitani, T. Sakanoi, Y. Kasaba

    Geophysical Research Letters   2018年11月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1029/2018gl079411

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  • Investigating Solar Wind‐Driven Electric Field Influence on Long‐Term Dynamics of Jovian Synchrotron Radiation 査読

    S. Han, G. Murakami, H. Kita, F. Tsuchiya, C. Tao, H. Misawa, A. Yamazaki, M. Nakamura

    Journal of Geophysical Research: Space Physics   2018年11月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1029/2018ja025849

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  • Study of the Solar Wind Influence on the Jovian Inner Magnetosphere Using an Ionospheric Potential Solver

    K Terada, C Tao, N Terada, Y Kasaba, H Kita, A Nakamizo, A Yoshikawa, S Ohtani, F Tsuchiya, M Kagitani, T Sakanoi, G Murakami, K Yoshioka, T Kimura, A Yamazaki, I Yoshikawa

    Proceeding of Lunar and Planetary Science Conference   49   2018年10月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

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  • Horizontal and vertical structures of Jovian infrared aurora: Observation using Subaru IRCS with adaptive optics 査読

    Hajime Kita, Shota Fujisawa, Chihiro Tao, Masato Kagitani, Takeshi Sakanoi, Yasumasa Kasaba

    Icarus   2018年10月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1016/j.icarus.2018.05.002

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  • Enhancement of the Jovian Magnetospheric Plasma Circulation Caused by the Change in Plasma Supply From the Satellite Io 査読

    F. Tsuchiya, K. Yoshioka, T. Kimura, R. Koga, G. Murakami, A. Yamazaki, M. Kagitani, C. Tao, F. Suzuki, R. Hikida, I. Yoshikawa, Y. Kasaba, H. Kita, H. Misawa, T. Sakanoi

    Journal of Geophysical Research: Space Physics   2018年8月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1029/2018ja025316

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  • Response of Jupiter's Aurora to Plasma Mass Loading Rate Monitored by the Hisaki Satellite During Volcanic Eruptions at Io 査読

    T. Kimura, Y. Hiraki, C. Tao, F. Tsuchiya, P. A. Delamere, K. Yoshioka, G. Murakami, A. Yamazaki, H. Kita, S. V. Badman, K. Fukazawa, I. Yoshikawa, M. Fujimoto

    Journal of Geophysical Research: Space Physics   2018年3月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2017ja025029

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  • Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 3. Volcanic Control of Jupiter's Aurora 査読

    Chihiro Tao, Tomoki Kimura, Fuminori Tsuchiya, Go Muirakami, Kazuo Yoshioka, Atsushi Yamazaki, Sarah V. Badman, Hiroaki Misawa, Hajime Kita, Yasumasa Kasaba, Ichiro Yoshikawa, Masaki Fujimoto

    Geophysical Research Letters   2018年1月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2017gl075814

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  • Feasibility of the exploration of the subsurface structures of Jupiter's icy moons by interference of Jovian hectometric and decametric radiation 査読

    Kumamoto, A, Y. Kasaba, F. Tsuchiya, H. Misawa, H. Kita, W. Puccio, J.-E. Wahlund, J. Bergman, B. Cecconi, Y. Goto, J. Kimura, T. Kobayashi

    Planetary Radio Emissions VIII, edited by G. Fischer, G. Mann, M. Panchenko, and P. Zarka, Austrian Academy of Sciences Press, Vienna   127 - 136   2017年8月

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

    DOI： 10.1553/PRE8s127

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  • Volcanic activity on Io and its influence on the dynamics of the Jovian magnetosphere observed by EXCEED/Hisaki in 2015 査読

    Ichiro Yoshikawa, Fumiharu Suzuki, Reina Hikida, Kazuo Yoshioka, Go Murakami, Fuminori Tsuchiya, Chihiro Tao, Atsushi Yamazaki, Tomoki Kimura, Hajime Kita, Hiromasa Nozawa, Masaki Fujimoto

    EARTH PLANETS AND SPACE   69   2017年8月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1186/s40623-017-0700-9

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  • A flux comparison of northern and southern Saturn kilometric radio bursts during southern summer 査読

    Kasaba, Y, T. Kimura, D. Maruno, A. Morioka, B. Cecconi, L. Lamy, C. M. Jackman, C. Tao, H. Kita, H. Misawa, T. Tsuchiya, A. Kumamoto

    Planetary Radio Emissions VIII, edited by G. Fischer, G. Mann, M. Panchenko, and P. Zarka, Austrian Academy of Sciences Press, Vienna   205 - 215   2017年8月

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

    DOI： 10.1553/PRE8s205

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  • Transient brightening of Jupiter's aurora observed by the Hisaki satellite and Hubble Space Telescope during approach phase of the Juno spacecraft 査読

    T. Kimura, J. D. Nichols, R. L. Gray, C. Tao, G. Murakami, A. Yamazaki, S. V. Badman, F. Tsuchiya, K. Yoshioka, H. Kita, D. Grodent, G. Clark, I. Yoshikawa, M. Fujimoto

    GEOPHYSICAL RESEARCH LETTERS   44 ( 10 )   4523 - 4531   2017年5月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER GEOPHYSICAL UNION  

    In early 2014, continuous monitoring with the Hisaki satellite discovered transient auroral emission at Jupiter during a period when the solar wind was relatively quiet for a few days. Simultaneous imaging made by the Hubble Space Telescope (HST) suggested that the transient aurora is associated with a global magnetospheric disturbance that spans from the inner to outer magnetosphere. However, the temporal and spatial evolutions of the magnetospheric disturbance were not resolved because of the lack of continuous monitoring of the transient aurora simultaneously with the imaging. Here we report the coordinated observation of the aurora and plasma torus made by Hisaki and HST during the approach phase of the Juno spacecraft in mid-2016. On day 142, Hisaki detected a transient aurora with a maximum total H-2 emission power of similar to 8.5 TW. The simultaneous HST imaging was indicative of a large "dawn storm," which is associated with tail reconnection, at the onset of the transient aurora. The outer emission, which is associated with hot plasma injection in the inner magnetosphere, followed the dawn storm within less than two Jupiter rotations. The monitoring of the torus with Hisaki indicated that the hot plasma population increased in the torus during the transient aurora. These results imply that the magnetospheric disturbance is initiated via the tail reconnection and rapidly expands toward the inner magnetosphere, followed by the hot plasma injection reaching the plasma torus. This corresponds to the radially inward transport of the plasma and/or energy from the outer to the inner magnetosphere.

    DOI： 10.1002/2017GL072912

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  • ひさき衛星を用いた木星紫外オーロラの太陽風応答に関する統計解析

    北 元, 木村 智樹, 垰 千尋, 土屋 史紀, 山崎 敦, 村上 豪, 吉岡 和夫, 坂野井 健, 笠羽 康正, 吉川 一朗, 藤本 正樹

    第17回宇宙科学シンポジウム 講演集   2017年

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  • Three-year of observations of Jupiter's aurora and Io plasma torus variabilities by earth orbiting extreme-ultraviolet spectroscope HISAKI 査読

    F. Tsuchiya, K. Yoshioka, T. Kimura, G. Murakami, C. Tao, H. Kita, I. Yoshikawa, A. Yamazaki, Y. Kasaba

    FRONTIERS IN THEORETICAL AND APPLIED PHYSICS/UAE 2017 (FTAPS 2017)   869 ( 1 )   UNSP 012069   2017年

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

    DOI： 10.1088/1742-6596/869/1/012069

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    その他リンク： http://orcid.org/0000-0002-8160-3553

  • WIDE-BAND SPECTRA of GIANT RADIO PULSES from the CRAB PULSAR 査読

    Ryo Mikami, Katsuaki Asano, Shuta J. Tanaka, Shota Kisaka, Mamoru Sekido, Kazuhiro Takefuji, Hiroshi Takeuchi, Hiroaki Misawa, Fuminori Tsuchiya, Hajime Kita, Yoshinori Yonekura, Toshio Terasawa

    Astrophysical Journal   832 ( 2 )   2016年12月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.3847/0004-637X/832/2/212

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  • Response of Jupiter's inner magnetosphere to the solar wind derived from extreme ultraviolet monitoring of the Io plasma torus 査読

    Go Murakami, Kazuo Yoshioka, Atsushi Yamazaki, Fuminori Tsuchiya, Tomoki Kimura, Chihiro Tao, Hajime Kita, Masato Kagitani, Takeshi Sakanoi, Kazunori Uemizu, Yasumasa Kasaba, Ichiro Yoshikawa, Masaki Fujimoto

    GEOPHYSICAL RESEARCH LETTERS   43 ( 24 )   12308 - 12316   2016年12月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2016GL071675

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  • Wide-Band Spectra of Giant Radio Pulses from the Crab Pulsar 査読

    Ryo Mikami, Katsuaki Asano, Shuta J. Tanaka, Shota Kisaka, Mamoru Sekido, Kazuhiro Takefuji, Hiroshi Takeuchi, Hiroaki Misawa, Fuminori Tsuchiya, Hajime Kita, Yoshinori Yonekura, Toshio Terasawa

    2016年8月

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    We present the results of the simultaneous observation of the giant radio
    pulses (GRPs) from the Crab pulsar at 0.3, 1.6, 2.2, 6.7, and 8.4 GHz with four
    telescopes in Japan. We obtain 3194 and 272 GRPs occurring at the main pulse
    and the interpulse phases, respectively. A few GRPs detected at both 0.3 and
    8.4 GHz are the most wide-band samples ever reported. In the frequency range
    from 0.3 to 2.2 GHz, we find that about 70\% or more of the GRP spectra are
    consistent with single power laws and the spectral indices of them are
    distributed from $-4$ to $-1$. We also find that a significant number of GRPs
    have such a hard spectral index (approximately $-1$) that the fluence at 0.3
    GHz is below the detection limit ("dim-hard" GRPs). Stacking light curves of
    such dim-hard GRPs at 0.3 GHz, we detect consistent enhancement compared to the
    off-GRP light curve. Our samples show apparent correlations between the
    fluences and the spectral hardness, which indicates that more energetic GRPs
    tend to show softer spectra. Our comprehensive studies on the GRP spectra are
    useful materials to verify the GRP model of fast radio bursts in future
    observations.

    DOI： 10.3847/0004-637X/832/2/212

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  • Very Long Baseline Interferometry Experiment on Giant Radio Pulses of Crab Pulsar toward Fast Radio Burst Detection 査読

    K. Takefuji, T. Terasawa, T. Kondo, R. Mikami, H. Takeuchi, H. Misawa, F. Tsuchiya, H. Kita, M. Sekido

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC   128 ( 966 )   2016年8月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1088/1538-3873/128/966/084502

    Web of Science

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  • Characteristics of solar wind control on Jovian UV auroral activity deciphered by long-term Hisaki EXCEED observations: Evidence of preconditioning of the magnetosphere? 査読

    Hajime Kita, Tomoki Kimura, Chihiro Tao, Fuminori Tsuchiya, Hiroaki Misawa, Takeshi Sakanoi, Yasumasa Kasaba, Go Murakami, Kazuo Yoshioka, Atsushi Yamazaki, Ichiro Yoshikawa, Masaki Fujimoto

    Geophysical Research Letters   2016年7月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2016gl069481

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  • Relation between the short-term variation of the Jovian radiation belt and thermosphere derived from radio and infrared observations 査読

    Kita Hajime, Misawa Hiroaki, Bhardwaj Anil, Tsuchiya Fuminori, Sakanoi Takeshi, Kasaba Yasumasa, Tao Chihiro, Miyoshi Yoshizumi, Morioka Akira

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   120 ( 8 )   6614 - 6623   2015年8月

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  • Relation between the short‐term variation of the Jovian radiation belt and thermosphere derived from radio and infrared observations 査読

    Hajime Kita, Hiroaki Misawa, Anil Bhardwaj, Fuminori Tsuchiya, Takeshi Sakanoi, Yasumasa Kasaba, Chihiro Tao, Yoshizumi Miyoshi, Akira Morioka

    Journal of Geophysical Research: Space Physics   2015年8月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2015ja021374

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  • Vertical emissivity profiles of Jupiter's northern H-3(+) and H-2 infrared auroras observed by Subaru/IRCS 査読

    T. Uno, Y. Kasaba, C. Tao, T. Sakanoi, M. Kagitani, S. Fujisawa, H. Kita, S. V. Badman

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 12 )   2014年12月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/2014JA020454

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  • Response of the Jovian thermosphere to variations in solar EUV flux 査読

    Chihiro Tao, Yoshizumi Miyoshi, Nick Achilleos, Hajime Kita

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 5 )   3664 - 3682   2014年5月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER GEOPHYSICAL UNION  

    Examining the response to solar extreme ultraviolet (EUV) radiation is an established diagnostic method used to understand the physics of planetary environments. In this study, we focus on the response of the Jovian thermosphere to variations in the solar EUV flux and discuss the consequences for the coupled thermosphere-ionosphere-magnetosphere system. We use a model that simulates both the thermospheric dynamics and the magnetospheric plasma velocity distribution under conditions of angular momentum transport between these regions. The simulations show that when the EUV flux increases by similar to 100% and 200%, the thermospheric neutral wind velocity at similar to 45 degrees latitude increases by 16% and 22%, respectively. The short-term variation over a few Earth days causes an increased velocity at middle latitudes which are magnetically conjugate to the Jovian radiation belt. Increased heating due to solar EUV contributes to this velocity change. The other contribution arises similar to 30 planetary rotations after the initial solar EUV flux increase. This second (delayed) effect is due to propagation of momentum from high latitudes (the auroral region), where Joule heating is dominant, and is related to the behavior of the ionospheric conductance and magnetosphere-ionosphere coupling currents. The modeled velocity enhancement is smaller than that required to explain the observed enhancement of the synchrotron emission by radial diffusion of the trapped energetic electrons. In this context, we discuss the sensitivity of the underlying thermosphere-ionosphere response to short-wavelength solar radiation and the ensuing three-dimensional wind fields.

    DOI： 10.1002/2013JA019411

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  • Response of the Jovian thermosphere to variations in solar EUV flux 査読

    Chihiro Tao, Yoshizumi Miyoshi, Nick Achilleos, Hajime Kita

    Journal of Geophysical Research: Space Physics   119 ( 5 )   3664 - 3682   2014年

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    記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Blackwell Publishing Ltd  

    DOI： 10.1002/2013JA019411

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  • Observations of Infrared and Synchrotron Emission from Jupiter during Sprint-A/EXCEED Campaign

    Kita, H, H. Misawa, F. Tsuchiya, S. Fujisawa, T. Sakanoi, Y. Kasaba

    2014惑星圏研究会集録   2014年

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    記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

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  • Effect of solar UV/EUV heating on the intensity and spatial distribution of Jupiter's synchrotron radiation 査読

    H. Kita, H. Misawa, F. Tsuchiya, C. Tao, A. Morioka

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   118 ( 10 )   6106 - 6115   2013年10月

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    記述言語：英語   掲載種別：研究論文（学術雑誌）  

    DOI： 10.1002/jgra.50568

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  • Effect of solar UV/EUV heating on the intensity and spatial distribution of Jupiter's synchrotron radiation 査読

    H. Kita, H. Misawa, F. Tsuchiya, C. Tao, A. Morioka

    Journal of Geophysical Research: Space Physics   118 ( 10 )   6105 - 6115   2013年

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    記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Blackwell Publishing Ltd  

    DOI： 10.1002/jgra.50568

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  • Two-element radio interferometer for the observation of Jupiter's synchrotron radiation 査読

    Tsuchiya, F, H. Misawa, H. Kita, A. Morioka, T. Kondo

    Proc. International Symposium on Planetary Science 2011   2013年

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    記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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MISC

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共同研究・競争的資金等の研究課題

  • 宇宙・地上望遠鏡・探査機・及びモデルを融合させた木星磁気圏の粒子加速に関する研究

    研究課題/領域番号：19H01948  2019年4月 - 2022年3月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    吉岡 和夫, 山崎 敦, 土屋 史紀, 木村 智樹, 北 元, 垰 千尋

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    配分額：16900000円 （ 直接経費：13000000円 、 間接経費：3900000円 ）

    本年度の繰り越し分の経費を用いて，イオ火山の活発化に伴うイオプラズマトーラスの高温電子輸送のパラメタ特定，とくに朝夕非対称性について議論を深めることができた．
    具体的には，ひさき衛星のデータの中から，５つのイオ火山イベントに関連するデータを抽出し，それらに対してスペクトルフィッティング手法を通してプラズマの密度および温度を導出する手法を確立した．これまでは，頻度の低い高分解モードでのスペクトルにしか適応できなかったこのパラメタ導出を，広視野（低分解能）モードのデータにも適用可能になる手法を確立したことにより，プラズマパラメタの導出を時間軸に拡張することに成功した．
    NASAのJuno探査機の研究チームのその場観測データと，米国コロラド大学の研究チームが開発しているモデルを組み合わせることで，ひさき衛星のデータから導出したパラメタとの整合性を確認できた．ただし，NASA/Juno探査機の高エネルギー電子やイオン観測装置などによる，木星内部磁気圏のその場観測データの解析に関しては，当初想定していたほどの進捗は見られなかった．これは主にCOVID-19による海外渡航の制限が主な原因であるが，今後は遠隔体制でも効率よくデータ解析できるシステムを構築する．また，小研究会の開催などを通して引き続き米国の研究チームと密に連絡を取り合うことで，校正データの共有などを高頻度で進める．なお，今年度の研究成果として国際学術論文誌２編と博士論文１件，修士論文４件が発表された．

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