资源环境科技发展态势分析平台

Dipolarization Front (DF) is an Alfvenic boundary separating the hot and tenuous plasma of magnetic reconnection downstream from the cold and dense ambient plasma sheet. Numerous studies have shown that the electric field at the front is mainly balanced by the Hall term. Charged particles are efficiently accelerated within the front and pile-up regions. However, the current system and associated particle dynamics in the front–plasma sheet interaction region ahead of the DF remain not well understood. Utilizing data from the Magnetospheric Multiscale (MMS) mission, we statistically investigate this region based on 70 DF events. Bipolar B_y is observed ahead of the DF, which results from earthward deflected ions and quasi-parallel/antiparallel electrons in the interaction region. Moreover, thermal electrons and ions above 4 keV are the main carriers of the current system. Our research reveals the Hall nature ahead of the DF.