太陽コロナホール加熱の新たなメカニズムを発見(Scientists Discover Locally Excited Slow-Mode Waves as Critical Coronal Heating Mechanism in Solar Coronal Holes)

2026-04-02 中国科学院(CAS)

中国科学院雲南天文台を中心とする研究チームは、太陽コロナ加熱問題に対し「局所励起スローモード波」という新たな加熱機構を提案した。従来、スローモード波は下層大気で減衰すると考えられていたが、本研究ではコロナホール内で再励起されることを数値シミュレーションと衛星観測で実証した。スピキュールによるプラズマ流入が波動と衝撃波を生み、10~100W/m²のエネルギーを供給し熱へ変換することが確認された。これにより、コロナ加熱の理論に新たな視点を提供し、太陽風起源の理解にも寄与する成果となった。

太陽コロナホール加熱の新たなメカニズムを発見(Scientists Discover Locally Excited Slow-Mode Waves as Critical Coronal Heating Mechanism in Solar Coronal Holes)
Numerical simulation results of solar spicules. (Image by NI Lei)

<関連情報>

太陽コロナホールにおける突発的なスピキュラー流に伴うエネルギーおよび物質輸送 Energy and Mass Transport Associated with Impulsive Spicular Flows in Solar Coronal Holes

Lei Ni, Jun Lin, Tanmoy Samanta, Guanchong Cheng, Yifu Wang, and Robert Erdélyi
The Astrophysical Journal Letters  Published: 2026 March 17
DOI:10.3847/2041-8213/ae4964

Abstract

How the solar atmosphere is heated from a temperature of about 5000 to 6000 K in the lower atmosphere to about 1–2 MK in the corona has challenged the astrophysical community for nearly 80 yr. The same puzzle exists for the stellar coronae heating as well. In this study, we present a series of findings on solar spicules and their subsequent impact on the corona within a coronal hole environment, characterized by locally open magnetic field lines, combining insights from MHD simulations with observations. We find that the convective and turbulent motions around the solar surface cause extensive shocks and small-scale magnetic reconnection in the lower atmosphere. The combined effects of shock compression and reconnection outflows then drive the formation of groups of spicules with a quasiperiod of about 300 s and a width of ∼200–500 km. The spicule upflows provide an averaged mass flux above 10−9 kg m−2 s−1 in the lower corona to sustain the solar wind in coronal holes, and they continuously trigger further new local slow-mode waves and shocks. These waves supply an energy flux of 10–100 W m−2 in the lower corona, and they are dissipated by heat conduction and compression heating to sustain the corona temperature of about 1 MK. The results also indicate that the upward propagating disturbances observed in extreme ultraviolet passbands are caused by both spicule upflows and slow-mode waves and shocks. Our findings help in understanding the long-standing problem of coronal heating and the origin of solar winds in coronal hole regions.

1702地球物理及び地球化学
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