MHD Simulation for Investigating Dynamic State Transition Responsible
for Solar Eruption in Active Region 12158
We presented a magnetohydrodynamic model of a solar eruption observed in Active Region 12158. In this model the effects of solar gravitational field and solar wind were taken into account, the latter of which may make the AR's magnetic structure deviate from a static state before the eruption. To achieve a quasi-static pre-eruptive state, we performed a three-dimensional MHD simulation in which a gas pressure-driven outflow was imposed as a solar wind on upper part of the coronal magnetic structure of the AR, which had been reconstructed via a nonlinear force-free field model from photospheric vector magnetic-field data. The simulation showed that an inner sheared loop (intermediate-height loop) had a dynamic state transition from the quasi-static pre-eruptive state to an eruptive state, which is essentially different from destabilization of static magnetic structure. We demonstrated that the dynamic state transition was associated with shape change of the loop from a vertically expanding shape to a vertically and laterally expanding shape, as suggested by κH-mechanism.
Reference
Lee H. H. & Magara T. 2018, Astrophysical Journal, 859, 132
