Observations of Electrostatic Solitary Waves in the Martian Magnetic Reconnection Exhaust Region

Abstract This study reports for the first time the occurrence of electrostatic solitary waves during a reconnection exhaust event observed by NASA’s Mars Atmosphere and Volatile Evolution mission on 2015 February 9 in the dayside Martian magnetosheath region. A total of seven burst events were analyzed, showing that the peak amplitudes of most solitary structures lie in the range of 1–4 mV m −1 , with pulse durations between 0.3 and 0.7 ms. The generation mechanism of these nonlinear waves is modeled by treating the reconnection exhaust region as an unmagnetized, multicomponent plasma composed of fluid H + , O + , O 2 + , and C O 2 + ions along with background superthermal electrons. The Sagdeev pseudopotential technique is used to analyze solitary waves with arbitrary amplitude. The theoretical model predicts positive potential ion acoustic solitons having bipolar electric fields with amplitudes of (1.4–3.4) mV m −1 and having pulse durations of (0.3–0.5) ms, which are in good agreement with the observed values in the reconnection exhaust region.