Two-Spacecraft Observations of Asymmetric Martian Bow Shock: Conjunctions of Tianwen-1 and MAVEN

Abstract

The Martian bow shock has been extensively studied through magnetic field and plasma instrument observations from various Mars space missions. However, prior investigations primarily involve statistical analyses based on single spacecraft crossings, leaving the asymmetry of the Martian bow shock unstudied through simultaneous two-spacecraft observations. In this study, utilizing simultaneous observations from Tianwen-1 and MAVEN, we examine the instantaneous asymmetry of the Martian bow shock. We present the asymmetry of the Martian bow shock in the Mars-Solar-Electric and Mars-Solar-Orbital reference frames, possibly influenced by the solar wind motional electric field and Martian crustal magnetic field, respectively. Moreover, we suggest that the bow shock exhibits increased asymmetry under stronger solar wind motional electric field conditions. This study highlights how a two-point observation approach offers valuable insights into the dynamic behavior of the Martian induced magnetosphere.