Challenge for comprehensive numerical calculation covering the whole convection zone

• Project/Area Number: 16K17655
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Chiba University
• Principal Investigator: Hotta Hideyuki 千葉大学, 大学院理学研究院, 特任助教 (10767271)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 太陽対流層 / 太陽熱対流 / 黒点 / 磁気流体力学 / 熱対流 / 光球 / 数値計算 / 太陽 / 乱流

Outline of Final Research Achievements

We develop the new numerical code for covering the whole convection zone. In the code, we treat the radiation energy loss as precise as possible and is applicable to the massive super computing. Using this numerical code, we carry out a comprehensive calculation of the solar convection zone for the first time. In addition, we also reproduce the formation of the sunspot in an unprecedentedly deep calculation domain.

Academic Significance and Societal Importance of the Research Achievements

本研究での成果には宇宙天気的な意義がある。太陽深部で発生する磁場は、黒点を形成し、しばしば太陽フレアなどの突発現象を引き起こし、地球にも影響を与える。この太陽深部→黒点の過程を明らかにしたことで、太陽で起こる爆発現象で根本の理解に繋がるであろう。また、太陽磁場生成については、まだ多くの謎が残っている。これは太陽内部を光で直接観測することができないことが原因の一つであるが、本研究では、世界で初めて太陽深部と観測可能な表面を繋げることができた。このことにより今後太陽深部での磁場生成についてさらなる理解が進むであろう。

Research Products

• [Journal Article] Weak influence of near-surface layer on solar deep convection zone revealed by comprehensive simulation from base to surface (2019)
  • Author(s): Hotta, H; Iijima, H.; Kusano K.
  • Journal Title: Science Advances Volume: 5 Issue: 1
  • DOI: 10.1126/sciadv.aau2307
  • Peer Reviewed / Open Access
• [Journal Article] Semiconservative reduced speed of sound technique for low Mach number flows with large density variations (2019)
  • Author(s): Iijima H.、Hotta H.、Imada S.
  • Journal Title: Astronomy & Astrophysics Volume: 622 Pages: A157-A157
  • DOI: 10.1051/0004-6361/201834031
  • Peer Reviewed / Open Access
• [Journal Article] Breaking Taylor-Proudman Balance by Magnetic Fields in Stellar Convection Zones (2018)
  • Author(s): Hotta, H
  • Journal Title: The Astrophysical Journal Volume: 860 Issue: 2 Pages: L24-L24
  • DOI: 10.3847/2041-8213/aacafb
  • Peer Reviewed
• [Journal Article] Asteroseismic detection of latitudinal differential rotation in 13 Sun-like stars (2018)
  • Author(s): Benomar, O.; Bazot, M.; Nielsen, M. B.; Gizon, L.; Sekii, T.; Takata, M.; Hotta, H.; Hanasoge, S.; Sreenivasan, K. R.; Christensen-Dalsgaard, J.
  • Journal Title: Science Volume: 361 Issue: 6408 Pages: 1231-1234
  • DOI: 10.1126/science.aao6571
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Sunspot drawings by Japanese official astronomers in 1749?1750 (2018)
  • Author(s): Hayakawa Hisashi、Iwahashi Kiyomi、Fujiyama Masashi、Kawai Toshiki、Toriumi Shin、Hotta Hideyuki、Iijima Haruhisa、Imada Shinsuke、Tamazawa Harufumi、Shibata Kazunari
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 70 Issue: 4 Pages: 63-63
  • DOI: 10.1093/pasj/psy066
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Convective Velocity Suppression via the Enhancement of the Subadiabatic Layer: Role of the Effective Prandtl Number (2017)
  • Author(s): Bekki, Y.; Hotta, H.; Yokoyama, T.
  • Journal Title: The Astrophysical Journal Volume: 851 Issue: 2 Pages: 74-74
  • DOI: 10.3847/1538-4357/aa9b7f
  • Peer Reviewed
• [Journal Article] Solar Overshoot Region and Small-scale Dynamo with Realistic Energy Flux (2017)
  • Author(s): Hotta, H
  • Journal Title: The Astrophysical Journal Volume: 843 Issue: 1 Pages: 52-52
  • DOI: 10.3847/1538-4357/aa784b
  • Peer Reviewed
• [Journal Article] Spatial Inhomogeneity of Kinetic and Magnetic Dissipations in Thermal Convection (2017)
  • Author(s): Hotta, H
  • Journal Title: The Astrophysical Journal Volume: 845 Issue: 2 Pages: 164-164
  • DOI: 10.3847/1538-4357/aa8320
  • Peer Reviewed
• [Journal Article] Improvement of solar-cycle prediction: Plateau of solar axial dipole moment (2017)
  • Author(s): Iijima, H.; Hotta, H.; Imada, S.; Kusano, K.; Shiota, D.
  • Journal Title: Astronomy & Astrophysics Volume: 607 Pages: 1-2
  • DOI: 10.1051/0004-6361/201731813
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Flux emergence simulation in a deep domain (2019)
  • Author(s): Hideyuki Hotta
  • Organizer: Flux emergence workshop 2019
  • Int'l Joint Research
• [Presentation] From solar dynamo to formation of sunspot (2019)
  • Author(s): Hideyuki Hotta, Haruhisa Iijima, Kanya Kusano
  • Organizer: MPPC meeting
  • Int'l Joint Research
• [Presentation] 黒点形成と太陽深部の磁場・熱対流構造の関係 (2019)
  • Author(s): 堀田英之
  • Organizer: 日本天文学会
• [Presentation] First comprehensive calculation of the whole solar convection zone (2018)
  • Author(s): Hideyuki Hotta, Haruhisa Iijima, Kanya Kusano
  • Organizer: 2018 SDO Science Workshop
  • Int'l Joint Research
• [Presentation] Solar and stellar convection and dynamo (2018)
  • Author(s): Hideyuki Hotta, Haruhisa Iijima, Kanya Kusano
  • Organizer: ITC27 & APPTC2018
  • Int'l Joint Research / Invited
• [Presentation] High Resolution Simulations of Solar Convection Zone and Dynamo (2018)
  • Author(s): Hideyuki Hotta, Haruhisa Iijima, Kanya Kusano
  • Organizer: AAPPS-DPP2018
  • Int'l Joint Research / Invited
• [Presentation] Calculation of solar convection zone with the reduced speed of sound technique (2018)
  • Author(s): Hideyuki Hotta, Haruhisa Iijima, Kanya Kusano
  • Organizer: International Astronomical Union
  • Int'l Joint Research / Invited
• [Presentation] 太陽内部と表面をつなぐ 大規模シミュレーション (2018)
  • Author(s): 堀田英之
  • Organizer: SGEPPS
  • Invited
• [Presentation] 黒点の拡散における太陽深部熱対流の影響 (2018)
  • Author(s): 堀田英之
  • Organizer: 日本天文学会
• [Presentation] 太陽の対流層の底から表面までの一貫した計算 (2018)
  • Author(s): 堀田英之, 飯島陽久, 草野完也
  • Organizer: 日本流体力学会
• [Presentation] 太陽の対流層の底から彩層下部までの一貫した初めての計算 (2018)
  • Author(s): 堀田英之, 飯島陽久, 草野完也
  • Organizer: 日本地球惑星科学連合
• [Presentation] Solar Convection Simulation with Reduced Speed of Sound Technique (2018)
  • Author(s): Hideyuki Hotta
  • Organizer: SIAM conference
  • Int'l Joint Research
• [Presentation] 対流層の底から光球までを包括した三次元熱対流計算 (2018)
  • Author(s): 堀田英之, 飯島陽久
  • Organizer: 日本天文学会
• [Presentation] Recent development of solar dynamo model (2017)
  • Author(s): Hideyuki Hotta
  • Organizer: Asia Pacific Solar Physics Meeting
  • Int'l Joint Research / Invited
• [Presentation] 太陽対流層の乱流と大規模流れ (2017)
  • Author(s): 堀田英之
  • Organizer: 気象学会
  • Invited
• [Presentation] テイラープラウドマン状態を破る磁場の役割 (2017)
  • Author(s): 堀田英之
  • Organizer: 日本天文学会
• [Presentation] 太陽のオーバーシュート層での小スケールダイナモについて (2017)
  • Author(s): 堀田英之
  • Organizer: 日本流体力学会
• [Presentation] Current understanding of solar dynamo (2017)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: NEXT22
  • Place of Presentation: 京都テルサ(京都・京都市)
  • Int'l Joint Research / Invited
• [Presentation] Solar global convection and dynamo with reduced speed of sound technique (2017)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: 7th AICS international symposium
  • Place of Presentation: 神戸大学(兵庫・神戸市)
  • Int'l Joint Research / Invited
• [Presentation] High-resolution calculation of solar dynamo (2017)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: MR2017
  • Place of Presentation: ひめぎんホール(愛媛・松山市)
  • Int'l Joint Research / Invited
• [Presentation] 熱対流の散逸について (2017)
  • Author(s): 堀田英之
  • Organizer: 日本天文学会
  • Place of Presentation: 九州大学(福岡・福岡市)
• [Presentation] ポスト京時代の太陽ダイナモ計算に向けて (2017)
  • Author(s): 堀田英之
  • Organizer: ポスト「京」萌芽的課題・計算惑星 第1回 公開シンポジウム：惑星の起源・進化と環境変動の解明を目指して
  • Place of Presentation: 神戸大学(兵庫・神戸市)
• [Presentation] Small-scale dynamo in the solar interior (2016)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: Solar and Stellar Magnetic Fields: a conference in honor of Manfred Schussler
  • Place of Presentation: Goslar, Germary
  • Int'l Joint Research / Invited
• [Presentation] Large-scale MHD simulation of solar convection zone and dynamo (2016)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: 6th East-Asia School and Workshop on Laboratory, Space, Astrophysical Plasmas
  • Place of Presentation: 国際会議場(茨城・つくば市)
  • Int'l Joint Research / Invited
• [Presentation] Small- and large-scale dynamos in the solar convection zone (2016)
  • Author(s): Hideyuki Hotta, Matthias Rempel, Takaaki Yokoyama
  • Organizer: ICPP2016
  • Place of Presentation: Kaohsiung, Taiwan
  • Int'l Joint Research / Invited
• [Presentation] 太陽の大スケールダイナモにおける小スケールダイナモの役割 (2016)
  • Author(s): 堀田英之
  • Organizer: 第6回 DTAシンポジウム「星形成を軸に俯瞰する磁場の役割とその観測的検証」
  • Place of Presentation: 国立天文台(東京・三鷹市)
  • Invited
• [Presentation] スーパーコンピューターを用いた太陽のシミュレーション (2016)
  • Author(s): 堀田英之
  • Organizer: サイエンティフィック・システム研究会[SS研]
  • Place of Presentation: ANAクラウンプラザホテル神戸(兵庫・神戸市)
  • Invited
• [Presentation] 京全ノードを用いた太陽対流層の超高解像度数値計算 (2016)
  • Author(s): 堀田英之, Matthias Rempel, 村主崇行, 牧野淳一郎
  • Organizer: 日本天文学会
  • Place of Presentation: 愛媛大学(愛媛・松山市)
• [Presentation] 磁場の効果を中心とした太陽オーバーシュート層の精密な調査 (2016)
  • Author(s): 堀田英之
  • Organizer: 日本天文学会
  • Place of Presentation: 愛媛大学(愛媛・松山市)
• [Presentation] 太陽ダイナモにおけるスケール間結合 (2016)
  • Author(s): 堀田英之
  • Organizer: プラズマシミュレータシンポジウム2016
  • Place of Presentation: 核融合研究所(岐阜・土岐市)
  • Invited
• [Presentation] Generation mechanism of .large-scale magnetic field .revealed with high-resolution .solar dynamo calculation (2016)
  • Author(s): 堀田英之, Matthias Rempel, 横山央明
  • Organizer: 日本地球惑星科学連合大会
  • Place of Presentation: 幕張メッセ(千葉県・千葉市)