On the Energy Conversion Rate during Collisionless Magnetic Reconnection

Magnetic reconnection efficiently converts magnetic energy into kinetic and thermal energy of plasmas. The electric field at the X-line, which represents the reconnection rate, is commonly used to measure how fast the reconnection proceeds. However, the energy conversion rate (ECR) has rarely been investigated. Using a 2.5D particle-in-cell simulation, we have examined the temporal evolution of the ECR in collisionless reconnection. It is found that the ECR reaches peak significantly later than the reconnection rate does. This is because the energy conversion primarily occurs at the reconnection fronts rather than at the X-line. With the increase of the inflow density, both the reconnection rate and the conversion rate decrease. The presence of a guide field leads to the reduction of both the reconnection rate and the conversion rate, though reconnection remains fast. We further find that ECR does not depend on the mass ratio but is sensitive to the length of the simulation domain.