Simulations of energy conversion and partition at dipolarization front

Dipolarization front plays a vital part in transporting magnetic flux energy in the magnetotail. Previous studies found that during magnetotail reconnection, the energy conversion process mainly occurs at the dipolarization front. However, the energy partition between ions and electrons among the released magnetic energy remains unclear. Using particle-in-cell simulations, we investigate the energy conversion and energy partition at the dipolarization front. It is found that the ion energy gain is 90% of the released magnetic energy while the electron energy gain is 10% of it. The main contribution of particle energization is Y component of energy conversion term. By introducing a moderate guide field B-y = 0.5 B-0, the ion energy gain increases to 95% of the released energy, while the electron energy gain is reduced to 5% of it. Meanwhile, due to the topology change of magnetic reconnection under the effect of a guide field, the contribution from Z component of energy conversion term is non-negligible. Our study advances understanding of the role that dipolarization front plays in particle energization and energy conversion in the magnetotail.