Ion dynamics and structure of collisionless shocks

Abstract: Shock waves are responsible for slowing down and heating supersonic flows. In collisionless space plasmas, shocks are able to accelerate particles to very high energies. We study injection of suprathermal ions at Earth’s quasi- parallel shock using high time resolution data from the Cluster spacecraft. We find that solar wind ions reflect off short large-amplitude magnetic structures (SLAMSs) and are subsequently accelerated by the convection electric field. We also use data from the closely-spaced Magnetospheric MultiScale (MMS) spacecraft to compare competing non-stationarity processes at Earth’s quasi- perpendicular bow shock. Using MMS’s high cadence plasma measurements, we find that the shock exhibits non-stationarity in the form of ripples.