Plasma acceleration in the Martian magnetotail observed by MAVEN

Since November 2014, the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has been collecting data from Mars's upper atmosphere and induced magnetosphere. Evidences of escaping planetary ions have been reported from earlier missions as Mars-Express and more recently from MAVEN. Our goal is to infer the significance of the acceleration mechanism responsible for the energization of heavy planetary ions in the Martian plasma sheet. According to Dubinin et al. (2011), the j x B force due to magnetic shear stresses of the draped field lines is expected to play a major role in such energization process. MAVEN has a full plasma package with a magnetometer and plasma particles instruments, which allow to address the question of plasma particle acceleration. We present observations of plasma sheet crossing events taking place in the Martian magnetotail between March 2015 and April 2016, using data from the magnetometer (MAG) and the ion mass spectrometer (STATIC). We present the results of the Walén test applied to these events in the commonly used DeHoffmann-Teller reference frame. Thanks to the results obtained from the Walén test, we can infer the importance of the j x B force.