Investigation of the Ion Reflection Rate at Quasi-Perpendicular Shocks

Particle reflection at collisionless shocks plays an important role in the dynamics of the shock layer. In this study we investigate the rate of ion reflection from quasi-perpendicular shocks under different upstream conditions. We use in-situ observations from NASA’s Magnetospheric Multiscale (MMS) Mission during 225 shock crossings as these shocks provide a wide range of parameters. For each event, different ion populations, including the solar wind and reflected ions are identified in the data, and associated plasma moments for each population are determined. We then looked at correlations between shock and plasma parameters, and ion reflection rate. These parameters include: ΙBΙ amplification rate, Alfvénic Mach Number (M_A), the shock angle (Θ_BN), upstream plasma density (n_Up), temperature, and velocity. We find that the reflection rate is not constant, and increases with the Alfvénic mach number and the magnetic amplification rate across the shock. This information will help further the understanding of the solar wind and how it interacts with our magnetosphere.