Examining the magnetic signal due to gravity and plasma pressure gradient current with the TIE-GCM

One of the challenges with processing LEO magnetic field measurements to study Earth's magnetic field is that the satellite flies in regions of highly varying ionospheric currents, which needs to be characterized accurately. The present study focuses on ionospheric current systems due to gravity and plasma pressure gradient forcing and aims to provide guidance on the estimation of their magnetic effect at LEO altitudes with the help of numerical modeling.

We assess the diamagnetic approximation that estimates the magnetic signal of the plasma pressure gradient current. The simulations indicate that the diamagnetic effect should not be removed from LEO magnetic observations without considering the gravity current effect, as this will lead to an error larger than the magnetic signal of these currents. We introduce and evaluate a method to capture the magnetic effect of the gravity-driven current.