Interplay of Three-Dimensional Instabilities and Magnetic Reconnection in the Explosive Onset of Magnetospheric Substorms

TL;DR

This paper investigates how three-dimensional instabilities and magnetic reconnection interact to trigger the explosive onset of magnetospheric substorms, using kinetic simulations to reveal the underlying physics.

Contribution

It introduces a kinetic simulation framework that captures the disruption of the dipolarization front by ballooning instability, advancing understanding of substorm initiation mechanisms.

Findings

Ballooning instability disrupts the dipolarization front.

Self-consistent particle tracking reveals acceleration mechanisms.

Simulations reproduce explosive substorm onset phenomena.

Abstract

Magnetospheric substorms are preceded by a slow growth phase of magnetic flux loading and current sheet thinning in the tail. Extensive datasets have provided evidence of the triggering of instabilities at substorm onset, including magnetic reconnection and ballooning instabilities. Using an exact kinetic magnetotail equilibrium we present particle-in-cell simulations which capture the explosive nature of substorms through a disruption of the dipolarization front by the ballooning instability. We use self-consistent particle tracking to determine the nonthermal particle acceleration mechanisms.