MAVEN Observations of the Interloop Magnetic Reconnections at Mars

Magnetic reconnection between neighboring magnetic field loops, so-called inter-loop reconnection, is a common process to drive flares in the solar atmosphere. However, there is no direct evidence that a similar but less explosive process can take place on planets. The strong crustal fields on Mars are capable of generating plenty of magnetic loops in the near Mars regions, which provides a unique environment to research the inter-loop reconnection on a planet. Here, we report magnetic reconnection events between crustal field loops in the Martian ionosphere observed by MAVEN for the first time. During the current layer crossing, signatures including Hall magnetic field, Alfvénic outflow, and electron energization were recorded, and the energized electrons exhibited auroral-like peaked electron distributions. This finding implies that the inter-loop reconnection in the Martian ionosphere could contribute to the localized energy deposition and particle energization, which provides the seed source for aurora in the Martian atmosphere.