Magnetosheath Jet Interaction with the Magnetopause: Results from the 3D hybrid-kinetic Simulation Amitis

Abstract

The magnetopause marks the boundary where the pressure of the magnetosheath balances the magnetic pressure of Earth’s magnetic field. Localized increases in magnetosheath pressure can therefore displace the magnetopause. One known plasma structure that exhibits such a local pressure increase is magnetosheath jets defined as transient dynamic pressure enhancements. These jets are particularly prominent downstream of the quasi-parallel bow shock, where they frequently interact with the magnetopause. To investigate the spatial and temporal characteristics of these interactions, we employ the 3D hybrid-kinetic plasma model Amitis with a steady plasma inflow. Our results show that jets downstream of the quasi-parallel bow shock can generate magnetopause surface waves that propagate flankward. Interestingly, while jets appear to have a similar velocity as the surface waves and continuously drive them, the jets apparent flankward motion does not align with the ion bulk velocity measured within the jets. This discrepancy may suggest ongoing jet generation at the bow shock, potentially linked to foreshock compressive structures.