Ion Instabilities in the Vicinity of the Earth’s Bow Shock Front in the Case of Weakly Magnetized Plasma

Abstract

The structure of the quasi-perpendicular bow shock of the Earth observed by the MMS spacecraft on 31 January 2017 with an Alfvén Mach number of approximately 10 and plasma parameter β of approximately 3, has been simulated using the Maximus hybrid kinetic code. We investigated types of instabilities governing the front structure and showed that in this case both ion Weibel and Alfvén ion cyclotron instabilities can arise at the shock foot simultaneously, thus leading to fast magnetic oscillations with a relative variation close to unity. Some signatures of the mirror instability were found in the near downstream. Simulation also showed that the front structure substantially differ for shock inclination angles of 50° and 75°.