Automated Bow Shock Identification and Multi-Spacecraft Timing Using Magnetospheric Multiscale (MMS) Observations

Abstract

Utilizing 8 years of dayside Magnetospheric Multiscale (MMS) mission plasma region identifications, we present an automatically identified and manually verified data set of 2,594 bow shock crossings in MMS burst-mode. For each bow shock crossing, we identify the bow shock ramp in each MMS probe using two automated methods and apply multi-spacecraft timing to calculate the bow shock normal. The bow shock list was separated into quasi-parallel and quasi-perpendicular based on the presence or absence of ion foreshock in order to evaluate deviations between the automated methods and a statistical 3D bow shock model. There are large discrepancies between global and local shock properties where the local shock properties are highly skewed towards quasi-perpendicular properties regardless of the presence of ion foreshock. Although this skewness grows when the tetrahedral configuration is suboptimal, it persists even under ideal formation, indicating that electron-scale processes can modulate local shock properties. These findings highlight the limitations of local multi-spacecraft timing in accurately characterizing shock geometry without contextual information, such as the presence of an upstream foreshock or a similarly disturbed downstream magnetosheath. Ultimately, this data article provides thousands of high-resolution bow shock crossings for further scientific research by the community.