Global Circulation of Martian Ionospheric Currents Revealed by Magnetometer Data

In the Dynamo Region of the Martian ionosphere a large-scale current is generated by collision of ions with the neutral wind while photoelectrons preferentially gyrate around local magnetic field lines. The direction and intensity of this current is locally determined by both the neutral wind velocity and ambient magnetic field. Using MAVEN magnetometer data, and a physics-informed neural network constrained by Ampere’s law of induction and Gauss's law for magnetism (the Neural-Curlometer technique), we compute a continuous high-resolution model of this current. We find that the ionospheric dynamo is located at altitudes of 125-200 km, is controlled by the interior magnetic field, and exhibits a clear seasonal variability. The currents coincide with the wind patterns theoretically estimated by global atmospheric circulation models and thus have the potential to significantly improve them.