A self-consistent model for coronal magnetic energy buildup and explosive eruption

Understanding the process for coronal magnetic field self-organization and energy buildup prior to an eruption is essential for determining the mechanism for CME onset. Distinguishing the trigger mechanism requires self-consistent calculation of the pre-eruptive field so that the evolution of the system is not artificially constrained. Recent theoretical and numerical studies have revealed a process by which helicity injected into the corona at small scales undergoes an inverse turbulent-like cascade that concentrates magnetic shear and energy at polarity inversion lines to form filament channels consistent with observations. We report on new 3D MHD simulations of this helicity condensation process in a spherical geometry favorable for an eruption. We show that energy buildup occurs in the form of a sheared arcade structure that eventually erupts. The eruption trigger is breakout reconnection in the field overlying the filament, and no flux rope forms until the subsequent onset of flare reconnection that drives explosive CME acceleration and energy release. These results have important implications for interpreting coronal observations and predicting CMEs. This work was supported by the NASA LWS, H-SR and ISFM programs.