Cross‐Shock Potential in Rippled Versus Planar Quasi‐Perpendicular Shocks Observed by MMS

Abstract

AbstractThe unprecedented detail of measurements by the four Magnetospheric Multiscale (MMS) spacecraft enable deeper investigation of quasi‐perpendicular collisionless shocks. We compare shock normals, planarities, and Normal Incidence Frame cross‐shock potentials determined from electric field measurements and proxies, for a subcritical interplanetary shock and a supercritical bow shock. The subcritical shock's cross‐shock potential was 26±6 V. The shock scale was 33 km, too short to allow comparison with proxies from ion moments. Proxies from electron moments provided potential estimates of 40±5 V. Shock normals from magnetic field minimum variance analysis were nearly identical, indicating a planar front. The supercritical shock's cross‐shock potential was estimated to be from 290 to 440 V from the different spacecraft measurements, with shock scale 120 km. Reflected ions contaminated the ion‐based proxies upstream, whereas electron‐based proxies yielded reasonable estimates of 250±50 V. Shock normals from electric field maximum variance analysis differed, indicating a rippled front.