Crustal magnetic fields' effect on the day-night transportation process in the Martian ionosphere

Mars is typically regarded as a non-magnetic planet. Currents in the Martian ionosphere generate a Venus-like induced magnetosphere to standoff the solar wind flows and to pile up the interplanetary magnetic fields. However, crustal magnetic fields in the southern hemisphere influence local plasma properties. Whether the crustal magnetosphere could be sustained is highly debatable and still uncertain. This work aims to provide evidence of a local crustal ’mini-magnetosphere’ in satellite observations on the Martian dayside, includes Mars Express, MAVEN, and Tianwen-1. The trapping effect causes different flow patterns while the crustal fields rotate to different sub-solar regions but are attenuated at higher altitudes. Observations provide essential information to investigate the effect of the crustal magnetic fields on heavy ion flows and understand the role of the crustal magnetic fields in the interaction between the solar wind and the Martian atmosphere.