The Evolution of Hot Flow Anomalies in Martian Space Environment

Hot Flow Anomalies (HFAs) are transient foreshock structures generated by solar wind discontinuity‐bow shock interactions, with their evolution only confirmed near Earth. Using MAVEN and Tianwen‐1 joint observations, we study the evolution of a Martian HFA event detected on 17 September 2022 (dayside by MAVEN, nightside by Tianwen‐1). The HFA retains a young‐type feature with negligible core magnetic fluctuations and little thickness change, but its trailing edge peak magnetic field drops by 46% (6.86–3.67 nT). We attribute the lack of young‐to‐mature evolution to Martian small bow shock, enabling HFA propagation upstream of the quasi‐perpendicular shock, precluding full development as Earth's HFAs.