Numerical Study of X-ray Jets from Coronal Hole in the Sun and Its Laboratory Investigation

Abstract:

A scenario for X-ray jets from coronal hole observed by Yohkoh and Hinode satellites was first suggested by Shibata based on magnetic reconnection from the Anemone structure [1]. A new possible scenario of solar flare eruption in the coronal hole has been developed and is analyzed by using MHD stability concepts for spheromak configuration. This talk presents the recent progress based on numerical simulation works. The stability properties of a spheromak partially embedded into a conducting surface are studied using three dimensional MHD simulations [2]. In agreement with analytical theory, a large degree of line-tying stabilizes the spheromak‘s tilt instability while the elongation has a destabilizing effect. High-resolution nonlinear simulations also demonstrate the current sheet formation at the upper surface of the spheromak, where the tilted magnetic field of the spheromak reconnects with the background magnetic field. The calculated stability threshold and the observed magnetic reconnection support a model of coronal jet eruptions where a dome-like magnetic structure grows through flux emergence on the solar surface, tilts, reconnects, and erupts. Countering the effect from elongation, line-tying strongly stabilizes a spheromak growing from a flux-emergence process, suggesting that in order for eruptive coronal jets to occur, there must be magnetic reconnection also at the bottom of the spheromak to detach the structure from the solar surface. A laboratory experiment is being planned to verify the results.

[1] K. Shibata, et al, Science 318, 1591 (2007).

[2] E. Belova et al., Phys. Plasmas 7, 4996 (2000)