Effects of stealth CME to ion energisation at ionospheric altitudes of Mars

Abstract

The declining phase of Solar cycle 24 produced a slow coronal mass ejection (CME), which was categorized as stealth CME based on the absence of associated low coronal signatures. This CME impacted Mars and caused a major space weather event during 27–28 August 2018 (max vsw = 580 km s−1 near 1.5 AU). The impact of the stealth CME on the topside of the Martian ionosphere is investigated using the data from Solar Wind Ion Analyzer (SWIA), Solar Energetic Particle (SEP) and Suprathermal and Thermal Ion Composition (STATIC) instruments onboard Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. The variations of ion and electron fluxes within the plasma boundaries during the passage of ICME event were observed using Electron Spectrometer (ELS) and the Ion Mass Analyzer (IMA) sensors onboard Mars Express (MEX) mission. The plasma boundaries of the induced magnetosphere of Mars showed considerable enhancement in the observed fluxes during the event. SWIA observations during the interaction of the CME with Martian plasma environment showed enhancement in the ion flux. STATIC observations showed energisation of planetary heavy ions like O+ and O2+ to energies between 10 eV up to hundreds of eV at altitudes below 300 km. SEP measurements of energetic O+ pick-up ions at energies below 50 keV further support the claim on planetary ion energisation.