Work

Dayside Magnetic Reconnection With Outflow Below the Mars' Escape Velocity: MAVEN Observation

Year: 2025

Type: article

Abstract: Previous studies have demonstrated that magnetic reconnection can cause ionospheric ions to escape from Mars. Using data from the Mars Atmosphere and Volatile Evolution (MAVEN) mission, we observed a dayside magnetic reconnection event with a jet speed of approximately 1.1 km/s, which is below Mars' escape velocity of 5 km/s. This event, characterized by a clear Hall magnetic field between draped interplanetary magnetic fields and open crustal field lines, was detected in the dayside ionosphere of the southern hemisphere. Due to the high density of heavy ions, the inflow Alfvén speed is low, around 2 km/s. Consequently, the reconnection jet, moving approximately at the inflow Alfvén speed, cannot escape Mars despite moving towards space. However, the reconnection significantly heated the ionospheric ions. Our findings may offer valuable insights into the study of similar processes, such as failed eruptions in the solar corona.

Source: Journal of Geophysical Research Planets

DOI: 10.1029/2024je008846