Electron Crescent Distributions as a Manifestation of Diamagnetic Drift in an Electron‐Scale Current Sheet: Magnetospheric Multiscale Observations Using New 7.5 ms Fast Plasma Investigation Moments

Author(s): Rager, AC; Dorelli, JC; Gershman, DJ; Uritsky, V; Avanov, LA; Torbert, RB; Burch, JL; Ergun, RE; Egedal, J; Schiff, C; Shuster, JR; Giles, BL; Paterson, WR; Pollock, CJ; Strangeway, RJ; Russell, CT; Lavraud, B; Coffey, VN; Saito, Y | Abstract: We report Magnetospheric Multiscale observations of electron pressure gradient electric fields near a magnetic reconnection diffusion region using a new technique for extracting 7.5 ms electron moments from the Fast Plasma Investigation. We find that the deviation of the perpendicular electron bulk velocity from E × B drift in the interval where the out-of-plane current density is increasing can be explained by the diamagnetic drift. In the interval where the out-of-plane current is transitioning to in-plane current, the electron momentum equation is not satisfied at 7.5 ms resolution.