Transport and entry of plasma clouds/jets across transverse magnetic discontinuities: Three-dimensional electromagnetic particle-in-cell simulations

TL;DR

This study uses 3D electromagnetic particle-in-cell simulations to explore how plasma clouds or jets interact with transverse magnetic discontinuities, revealing mechanisms for their transport and entry across magnetic barriers relevant to Earth's magnetosphere.

Contribution

It demonstrates the kinetic effects and electric fields enabling plasma jets to penetrate magnetic barriers, providing insights into magnetopause dynamics during northward interplanetary magnetic field conditions.

Findings

Polarization electric field facilitates plasma jet transport.

Jet penetration depends on the magnetic barrier height.

Jets are deflected and pushed back when conditions are unfavorable.

Abstract

In this paper we use three-dimensional electromagnetic particle-in-cell simulations to investigate the interaction of a small-Larmor radius plasma cloud/jet with a transverse non-uniform magnetic field typical to a tangential discontinuity in a parallel geometry. The simulation setup corresponds to an idealized, yet relevant, magnetospheric configuration likely to be observed at the magnetopause during northward orientation of the interplanetary magnetic field. The numerical simulations are adapted to study the kinetic effects and their role on the transport and entry of localized plasma jets similar to those identified inside the Earth's magnetosheath propagating towards the magnetopause. The simulations reveal the formation of a polarization electric field inside the main bulk of the plasma cloud that enables its forward transport and entry across the transverse magnetic field. The jet is able to penetrate the transition region when the height of the magnetic barrier does not exceed a certain critical threshold. Otherwise, the forward transport along the injection direction is stopped before full penetration of the magnetopause. Moreover, the jet is pushed back and simultaneously deflected in the perpendicular plane to the magnetic field. Our simulations evidence physical processes advocated previously by the theoretical model of impulsive penetration and revealed in laboratory experiments.