κH-mechanism for producing solar eruption
We present a magnetohydrodynamic model of solar eruption that self-consistently explains how an emerging magnetic field evolves toward the eruption. In this model a twisted flux tube emerges below a solar surface to form pre-eruptive magnetic structure in a dynamic state on the Sun, which is composed of a flux rope that eventually erupts and an expanding shearless arcade that overlies the flux rope. A key point of the model is that the eruption is inherent in nature of the emerging
twisted flux tube, which is represented by two factors: field-line curvature (κ) and field-strength scale height (H) of the emerging magnetic field (Magara 2013).
We investigated stability and dynamics of a flux rope produced by one such emerging twisted flux tube. A three-dimensional magnetohydrodynamic simulation was performed to derive
several key factors relevant to the stability and dynamics. The stability was examined by calculating
the decay index of an envelope field (= shearless arcade overlying the flux rope) according to Kliem & Török (2006). Regarding the dynamics, we demonstrated
a transition from a quasi-static state to eruptive state of the flux rope by analyzing spatial distributions of κ and H, which led us to κH-mechanism for producing solar eruption.
Reference
Kliem, B. & Török, T. 2006, PhRvL, 96, 255002
Magara, T. 2013, PASJ, 65, L5
An, J. M. & Magara, T. 2013, ApJ, 773, 21
Zhang, J. et al. 2001, ApJ, 559, 452
