JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM12] [EE] Space Weather, Space Climate, VarSITI

2017年5月23日(火) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:片岡 龍峰(国立極地研究所)、Antti A Pulkkinen(NASA Goddard Space Flight Center)、草野 完也(名古屋大学宇宙地球環境研究所)、塩川 和夫(名古屋大学宇宙地球環境研究所)

[PEM12-P07] Study of double arc instability causing the onset of solar eruption

*石黒 直行1草野 完也1 (1.名古屋大学 宇宙地球環境研究所 総合解析研究部)

キーワード:Sun, flares, instability

The stability of magnetic flux rope in the solar corona is an important issue for the understanding what causes solar eruptions, such as solar flares and coronal mass ejections (CMEs). Although various scenario has been suggested for this problem, the tether-cutting reconnection scenario suggested by Moore et al. (2001) is widely accepted. However the stability of double arc loop, which can be formed by tether-cutting reconnection of sheared magnetic field before eruption, has not been analyzed yet.
To explain such a solar eruption based on the tether-cutting reconnection model, recently we suggested Double Arc Instability (DAI). In this theory, we numerically analyzed the stability of double arc electric current loop in the same method as the axisymmetric torus instability developed by Demoulin & Aulanier (2010). As a result, we found that the double arc loop is more easily destabilized than the axisymmetric torus, and that it becomes unstable even if the external field is not decayed with altitude in contrast to the axisymmetric torus instability. It suggests that the tether-cutting reconnection can efficiently work as the onset mechanism of solar eruption, and that the decay index does not necessarily need to be larger than a criteria to trigger solar eruptions, while the torus instability can play a role in the full eruption of the flux rope to inter-planetary space. We discuss the critical conditions for the DAI to grow in the force-free magnetic field and derive that the critical parameter , which is defined as the product of the magnetic twist and the normalized tether-cutting reconnecting flux, must be larger than a certain threshold to destabilize DAI. Finally, we develop three-dimensional MHD simulation of the DAI to analyze the onset process of solar eruption in more realistic configuration of magnetic field.