Global explicit particle-in-cell simulations of the nonstationary bow shock and magnetosphere

TL;DR

This study uses high-resolution 2D particle-in-cell simulations to explore the formation and dynamics of the bow shock and magnetosphere, revealing self-reformation processes, magnetic reconnection, and complex plasma behaviors under various solar wind conditions.

Contribution

First global PIC simulations of the bow shock and magnetosphere that demonstrate self-reformation and plasma leakage phenomena under different solar wind parameters.

Findings

Self-reforming bow shock observed after several ion cyclotron periods.

Magnetic reconnection occurs in the magnetotail under certain conditions.

Downstream plasma behavior is more complex than in local planar shock models.

Abstract

We carry out two-dimensional global particle-in-cell simulations of the interaction between the solar wind and a dipole field to study the formation of the bow shock and magnetosphere. A self-reforming bow shock ahead of a dipole field is presented by using relatively high temporal-spatial resolutions. We find that (1) the bow shock and the magnetosphere are formed and reach a quasi-stable state after several ion cyclotron periods, and (2) under the Bz southward solar wind condition the bow shock undergoes a self-reformation for low \b{eta}i and high MA. Simultaneously, a magnetic reconnection in the magnetotail is found. For high \b{eta}i and low MA, the shock becomes quasi-stationary, and the magnetotail reconnection disappears. In addition, (3) the magnetopause deflects the magnetosheath plasmas. The sheath particles injected at the quasi-perpendicular region of the bow shock can be convected to downstream of an oblique shock region. A fraction of these sheath particles can leak out from the magnetosheath at the wings of the bow shock. Hence, the downstream situation is more complicated than that for a planar shock produced in local simulations.