Ionospheric Electric Current System Responsible for Daily Variations of Martian Magnetic Field as Recovered from MAVEN Data

Abstract:

Starting from September 2014 the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures vector magnetic field in an altitude range 125 – 6200 km covering all local times. We use the low altitude daytime magnetic field data to determine the geometry and amplitude of electric current system flowing in the ionosphere, which is likely the primary driver of observed daily magnetic field variations on Mars. The adopted approach is based on a potential representation of the magnetic field, prior electrical conductivity profile of Martian interior, and spherical harmonic parameterization of the potential. We will show and discuss the spatial structure of the estimated current system and its seasonal variability. Finally, we compare ground daily variations as measured by the InSight magnetometer with variations we calculate by using the MAVEN recovered ionospheric current.