第九届青年地学论坛

Investigating the physical mechanism of ion escape on Mars is crucial for comprehending the evolution of Martain space environment. The plume structure situated in the northern hemisphere of Mars serves as a significant pathway for planetary ion escape, contributing more than 20 percent to the overall ion escape rate. In this study, a three-dimensional multi-fluid Hall MHD numerical model is utilized to simulate the ion escape process of Mars. A force analysis is conducted to examine the electric field exerted on O⁺ and to investigate the density, velocity and escape flux of O⁺. Numerical results indicate that both the convection electric force and the Lorentz force play essential roles in driving ion escape in the plume region and shaping the morphology of ion eacaping fluxes. The plume is positioned above the magnetic pile-up boundary (MPB), as the convection electric field dicrected towards the +Z direction primarily influences the area above the MPB. Furthermore, the Hall electric field electric field points outward and reaches the peak values at the MPB, while the ambipolar electric field peaks at the bow shock (BS). In addition, the ions escaping from the plume predominantly originates from middle and high latitudes of the +E hemisphere on the Martian dayside. The plume escape rate is  4.33×10²³s^-1, while the tailward escape’s is 1.74×10²⁴s^-1. The plume escape rate accounts for 24.83% of the tail escape rate and 19.89% of the overall escape rate.

Mars,Numerical simulation,Martian plume escape,Martain electric field distribution