MHD Simulations for the Origin and Magnetic Topology of Solar3He Events

Abstract

The origin and magnetic topology of impulsive solar energetic particle (SEP) events (also called solar 3He-rich events) are numerically investigated by using a three-dimensional axisymmetric time-dependent self-consistent magnetohydrodynamic (MHD) model. The results indicate that when a counterclockwise (or normal) magnetic flux rope is emerged from the photosphere at the open field region near the closed magnetic field lines, the magnetic topology produced by the MHD simulation is that proposed by Reames to lead to impulsive SEP events. The flux emergence initiates the magnetic configuration which produces the magnetic reconfiguration and reconnection at the coronal base. The magnetic reconnection at the coronal base strongly disturbs the magnetic fields in the solar corona and interplanetary space, and generates fast jetlike plasma outflows (or non-flux-rope coronal mass ejections). The magnetic field line disturbances could scatter charged particles and therefore accelerate them to high energies through the Fermi acceleration mechanism.