Terrestrial Bow Shock Parameters From MMS Measurements: Dependence on Upstream and Downstream Time Ranges

We have investigated the dependence of shock parameters (speed vsh, normal n̂, and angle θBn) on the choice of upstream and downstream regions for 51 bow shock crossings in Magnetospheric Multiscale (MMS) Fast Survey data. We summarize guidelines for selecting stream regions based on the magnetic field and particle moments. Preferred upstream and downstream combinations were identified by minimizing Rankine‐Hugoniot conservation errors. Comparing parameters from different upstream/downstream combinations provided a measure of how stream region choices affect the parameters. Shifting from the preferred stream region combination to another would cause