Ion Jets Within Current Sheets in the Martian Magnetosphere

Abstract

Magnetic reconnection is often suggested to be implicated in a variety of dynamic phenomena observed in the complex magnetosphere of Mars. We present a first global survey of ion jets within current sheets, which are thought of as a primary product of magnetic reconnection, with Mars Atmosphere and Volatile EvolutioN (MAVEN) data obtained on the dayside and nightside in the Martian magnetosphere. We develop a fully automated algorithm to efficiently and reliably identify ion flow velocity deviations during current sheet crossings recorded by MAVEN. The obtained statistical results show that (i) sunward and anti-sunward ion jets embedded within current sheets are commonly and widely observed in the dayside and nightside magnetosphere of Mars, (ii) measured magnetic field profiles and inferred magnetic topology during the jet crossings are generally consistent with those expected for reconnecting current sheets, (iii) the jet occurrence is apparently independent of upstream driver conditions, and (iv) most of the identified current sheets are thin with a roughly ion scale half-thickness and are embedded in low beta plasma, suggesting that they are seemingly capable of reconnection based on the known onset conditions. The widespread distributions and common detection of ion jets, as well as the ubiquitous presence of thin, low-beta current sheets, imply that magnetic reconnection could operate frequently in many locations around Mars, thereby playing an important role in the dynamics of the Martian magnetosphere for most, if not all, of the solar wind conditions in the present epoch.