Dawn‐dusk asymmetry in bursty hot electron enhancements in the midtail magnetosheath

摘要: Bursty (a few minutes) enhancements of hot electrons (1–10 keV) in the tail magnetosheath, which we name electron (HEEs), are sometimes observed. To understand processes leading to HEEs, have used 4 years measurements from Acceleration Reconnection Turbulence and Electrodynamics Moon's Interaction with Sun mission statistically investigate dawn-dusk asymmetry HEEs midtail (x −30 −70 RE) magnetosheath their correlations solar wind/interplanetary magnetic field (IMF) conditions. We find two strong asymmetries associated HEEs: (1) they occur about 3 4 times more frequently on dawnside. (2) Their fluxes dawnside twice as large those duskside. The magnitudes HEE similar magnetosphere near magnetopause, also a factor 2 higher dawnside, indicating that likely source for cause flux asymmetry. preferentially during wind speed, majority sharp IMF direction changes accompanied by transient density changes. These stronger suggesting perturbations created quasi-parallel bow shock, is most time discontinuities possible process could account occurrence