太陽系科学研究系
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(兼任)宇宙科学研究所 高感度太陽紫外線分光観測衛星(SOLAR-C)プロジェクトマネージャー東京大学 教授(委)
- 学位
- 博士(理学）(1995年3月 東京大学)
- J-GLOBAL ID
- 200901047809298943
- researchmap会員ID
- 0000202790
- 外部リンク
太陽活動やコロナ加熱問題など、私たちの母なる星「太陽」およびその関連テーマに関して、人工衛星等の飛翔体による観測手段を用いて研究を行っています。2006年から軌道上で運用を続ける「ひので」（SOLAR-B）、観測ロケットや大気球、そして2020年代中盤に飛翔させる公募型小型4号機 SOLAR-Cによる先進的観測実現を可能にする搭載機器や衛星システムの開発にも取り組んでいます。SOLAR-Cには、世界初となる高分解能・高感度のEUV分光望遠鏡EUVSTを搭載します。
経歴
2-
2005年4月 - 現在
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1998年1月 - 2005年3月
主要な委員歴
1受賞
1主要な論文
222-
Solar Physics 300(5) 2025年5月30日Abstract In July 2024, Sunrise completed its third successful science flight. The Sunrise iii observatory had been upgraded significantly after the two previous successful flights in 2009 and 2013, to tackle the most recent science challenges concerning the solar atmosphere. Three completely new instruments focus on the small-scale physical processes and their complex interaction from the deepest observable layers in the photosphere up to chromospheric heights. Previously poorly explored spectral regions and lines are exploited to paint a three-dimensional picture of the solar atmosphere with unprecedented completeness and level of detail. The full polarimetric information is captured by all three instruments to reveal the interaction between the magnetic fields and the hydrodynamic processes. Two slit-based spectropolarimeters, the Sunrise UV Spectropolarimeter and Imager (SUSI) and the Sunrise Chromospheric Infrared spectro-Polarimeter (SCIP), focus on the near-ultraviolet (309 – 417 nm) and the near-infrared (765 – 855 nm) regions respectively, and the imaging spectropolarimeter Tunable Magnetograph (TuMag) simultaneously obtains maps of the full field-of-view of $46\times 46$ Mm2 in the photosphere and the chromosphere in the visible (525 and 517 nm). The instruments are operated in an orchestrated mode, benefiting from a new Image Stabilization and Light Distribution unit (ISLiD), with the Correlating Wavefront Sensor (CWS) providing the autofocus control and an image stability with a root-mean-square value smaller than 0.005”. A new gondola was constructed to significantly improve the telescope pointing stability, required to achieve uninterrupted observations over many hours. Sunrise iii was launched successfully on 10 July 2024, from the Esrange Space Center of the Swedish Space Corporation near Kiruna (Sweden). It reached the landing site between the Mackenzie River and the Great Bear Lake in Canada after a flight duration of 6.5 days. In this paper, we give an overview of the Sunrise iii observatory and its instruments.
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The Astrophysical Journal 983(2) 126-126 2025年4月15日Abstract Unstable states of the solar coronal magnetic field structure result in various flare behaviors. In this study, we compared the confined and eruptive flares that occurred under similar magnetic circumstances in the active region 12673, on 2017 September 6, using the twist number, decay index, and height of magnetic field lines to identify observational behaviors of the flare eruption. We investigated the parameters from the magnetic field lines involved in an initial energy release, which were identified from the positions of the core of flare ribbons, i.e., flare kernels. The magnetic field lines were derived by nonlinear force-free field modeling calculated from the photospheric vector magnetic field obtained by the Solar Dynamics Observatory SDO/Helioseismic and Magnetic Imager, and flare kernels were identified from the 1600 Å data obtained by the SDO/Atmospheric Imaging Assembly. The twist number of all the magnetic field lines in the confined flare was below 0.6; however, the twist number in seven out of 24 magnetic field lines in the eruptive flare was greater than 0.6. These lines were tall. It is found that the decay index is not a clear discriminator of the confined and eruptive flares. Our study suggests that some magnetic field lines in the kink instability state may be important for eruptive flares, and that taller magnetic field lines may promote flare eruption.
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The Astrophysical Journal 965(2) 136-11page 2024年4月 査読有り最終著者責任著者
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The Astrophysical Journal 2023年6月1日
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The Astrophysical Journal 943(2) 96-96 2023年1月27日 査読有りAbstract Magnetic helicity is a physical parameter used to quantify the complexity of magnetic fields, providing an indication of the energy state in the coronal magnetic structure. We investigate the temporal evolution of magnetic helicity and its relationship to the occurrence of a variety of flares in the solar active region NOAA 12297, which was well observed using the Solar Dynamics Observatory/Helioseismic and Magnetic Imager in 2015 March. The active region produced many M-class flares and an X-class flare in two distinctive areas, both of which had a similar magnetic evolution, i.e., the opposite polarity of an emerging flux developed beside a preexisting sunspot, but exhibited flares with different magnitudes and frequencies. We derived the spatiotemporal evolution of the magnetic helicity injections and evaluated how spinning and braiding helicity injections evolved with time in the two areas. In one area, we observed a remarkable evolution, in which a negative spinning helicity injection in the preexisting sunspot increased in a positive helicity system, followed by the occurrence of the X-class flare. The negative helicity injection was clearly caused by the flux emergence that developed along the outer edge of the preexisting sunspot. The other area showed positive braiding helicity injections, with spinning helicity injections fluctuating concurrently with flux emergence, changing their signs several times, i.e., variable energy, and helicity input. The observed temporal behaviors of the helicity injections may explain different types of flare occurrences in the regions.
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Solar Physics 297(9) 2022年9月 査読有り
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Frontiers in Astronomy and Space Sciences 9 908249 2022年6月13日 査読有りNanoflares and the shock formation of magnetohydrodynamic waves in the solar chromosphere have been considered as key physical mechanisms of the heating of the chromosphere and corona. To investigate candidates of their signature in the mm-wavelength, a tiny active region located on the solar disk was observed with the Atacama Large millimeter and sub-millimeter Array (ALMA) at 3 mm, coordinated with observatories on orbit including Hinode SOT spectro-polarimeter in the Cycle 4 solar campaign (19 March 2017). ALMA’s spatial resolution was moderate, far from the best performance, but it provided stable conditions that are suitable to investigate temporal variations in the mm-wavelength. We determined that the noise level is less than 20 K (σ) over 1 hour in the 20-s cadence time series of synthesized ALMA images. The time variations with amplitudes above the noise level were observed throughout the field of view, but variations exceeding 200 K, corresponding to energy input to the chromosphere on the order of 1020-22 erg, were localized in two locations. One location was on the polarity inversion line, where tiny concentrated magnetic patches exist in weak field and a tiny magnetic flux may be emergent. The other location was at the outer edge of a bipolar magnetic region, which was under development with a successive series of magnetic flux emergence. This observation suggests that nanoflare-class energy inputs in the chromosphere can occur associated with emerging flux activities.
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The Astrophysical Journal 2021年12月1日 査読有り筆頭著者責任著者
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The Astrophysical Journal 900(1) 34-34 2020年8月28日 査読有り
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The Astrophysical Journal 898(1) 32-32 2020年7月20日 査読有り最終著者
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The Astrophysical Journal 895(2) 105-105 2020年6月2日 査読有り最終著者
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The Astrophysical Journal 890(2) 141-141 2020年2月21日 査読有り最終著者
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Publications of the Astronomical Society of Japan, 71(5) R1 2019年10月 査読有り
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Proc. SPIE: UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXI 11118 1111807 2019年9月9日 筆頭著者責任著者
MISC
79-
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI 157-157 2024年8月26日
書籍等出版物
5-
Astronomical Society of Pacific: San Francisco 2012年
主要な講演・口頭発表等
35担当経験のある科目(授業)
1-
2022年4月 - 現在宇宙惑星科学特論III (東京大学大学院理学系研究科)
共同研究・競争的資金等の研究課題
13-
日本学術振興会 科学研究費助成事業 基盤研究(S) 2018年6月 - 2023年3月
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日本学術振興会 科学研究費助成事業 新学術領域研究(研究領域提案型) 2015年6月 - 2020年3月
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日本学術振興会 科学研究費助成事業 基盤研究(S) 2015年5月 - 2020年3月
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日本学術振興会 科学研究費助成事業 2018年4月 - 2019年3月
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日本学術振興会 科学研究費助成事業 2011年4月 - 2015年3月
学術貢献活動
1-
企画立案・運営等, パネル司会・セッションチェア等Hinode-13/IPELS 2019 LOC 2019年9月2日 - 2019年9月6日
社会貢献活動
13メディア報道
4-
市民タイムス https://www.shimintimes.co.jp/news/2024/07/post-26319.php 2024年7月 新聞・雑誌
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ニュートンプレス Newton 2024年5月号 https://www.newtonpress.co.jp/dcms_media/image/Newton202405_102-103.jpg 2024年5月 新聞・雑誌
