Characteristics of Electron Pitch-angle Distribution in the Flapping Magnetotail

Abstract The configuration, local motions, and related physics processes of the terrestrial magnetotail have been well studied, playing a key role in dynamics. But characteristics electron pitch-angle distribution (PAD), formation mechanisms, at different regions flapping were not pointed out. Here, we study current sheet crossing event detected by Magnetospheric Multiscale Mission inside magnetotail, investigate PAD detail. When spacecraft are out sheet, low-energy high-energy electrons present field-aligned cigar-type PAD, respectively. This difference shows motions electrons. We proposed two possible explanation mechanisms: newly dipolarized or exhaust region reconnection region, discussed them paper adequately. Based on mechanism, for first time, point that bouncing could be indicator magnetotail. In addition, four other cases with similar signatures observed. Our improves understanding dynamics configuration physics.