Energetic Electron Acceleration at Anti-Dipolarization Front Within the Magnetotail Reconnection Diffusion Region

Anti-dipolarization front (ADF), characterized by the sharp increase of the southward magnetic field (B_Z,GSM < 0), is a magnetic structure with reconnected magnetic field enhancement in the magnetotail reconnection. It is considered to be an important region for energy conversion in the tailward reconnection jet. In this paper, we report an ADF event within the magnetotail reconnection diffusion region, which may comprise two ADFs and exhibit a significant enhancement of energetic electron flux. We analyze the corresponding electron acceleration mechanisms and find that the Fermi acceleration dominates the local electron energy gain, contributing to the production of energetic electrons. The magnetic mirror effect and large-scale parallel electric potential may effectively trap the energetic electrons and facilitate Fermi acceleration. Our study provides important information for further understanding the mechanisms of energetic electron generation in space plasma.