Inoue Satoshi, Kusano Kanya, Büchner Jörg, Skála Jan
Max-Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077, Göttingen, Germany.
Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
Nat Commun. 2018 Jan 12;9(1):174. doi: 10.1038/s41467-017-02616-8.
Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the dynamics of a solar eruption in a real magnetic environment. In our simulation, we confirmed that tether-cutting reconnection occurring locally above the polarity inversion line creates a twisted flux tube, which is lifted into a toroidal unstable area where it loses equilibrium, destroying the force-free state, and driving the eruption. Consequently, a more highly twisted flux tube is built up during this initial phase, which can be further accelerated even when it returns to a stable area. We suggest that a nonlinear positive feedback process between the flux tube evolution and reconnection is the key to ensure this extra acceleration.
太阳爆发是极端空间天气的著名驱动因素，它会极大地扰乱地球的磁层和电离层。这些爆发的触发过程和初始动力学仍然是一个深入研究的领域。在这里，我们进行了磁流体动力学模拟，考虑了观测到的光球磁场，以揭示真实磁环境中太阳爆发的动力学。在我们的模拟中，我们证实了在极性反转线局部上方发生的系绳切断重联会产生一个扭曲的磁通管，该磁通管被提升到一个环形不稳定区域，在那里它失去平衡，破坏无力状态，并驱动爆发。因此，在这个初始阶段会形成一个扭曲程度更高的磁通管，即使它回到稳定区域，也可以进一步加速。我们认为，磁通管演化和重联之间的非线性正反馈过程是确保这种额外加速的关键。
