Energy Conversion during Asymmetric Magnetic Reconnection

Asymmetric magnetic reconnection usually occurs at the Earth’s magnetopause, where the magnetic field strength and plasma density are different between the magnetosheath and magnetosphere. In this paper, a two-dimensional particle-in-cell simulation model is used to study the energy conversion during asymmetric magnetic reconnection. Energy conversion can occur in the vicinity of the X-line, magnetosphere separatrix region, and reconnection fronts. In the vicinity of the X-line and magnetosphere separatrix region, the electromagnetic field energy is mainly transferred to electrons, while at the reconnection fronts, the electromagnetic field energy is mainly transferred to ions. For the case with weak magnetic field asymmetry, the reconnection fronts dominate the energy conversion, which is related to the inflowing Poynting flux S z at the fronts. For the case with strong magnetic field asymmetry, the energy conversion occurs around the X-line and magnetosphere separatrix region, but no longer at the reconnection fronts. This is because the inflowing Poynting flux S x near the magnetosphere separatrices provides electromagnetic energy for energy conversion. The density asymmetry has no significant effect on the spatial distribution of the energy conversion.