Influence of finite ion Larmor radius on the dynamics of weakly-collisional plasma jets colliding in magnetic arch

TL;DR

This study investigates how the finite ion Larmor radius influences the behavior of weakly-collisional plasma jets in magnetic arches, revealing scale-dependent dynamics including magnetic reconnection and transition to ideal MHD regimes.

Contribution

It provides new insights into the scale-dependent effects of ion Larmor radius on plasma jet interactions and magnetic arch evolution using hybrid numerical simulations.

Findings

More intense interaction dynamics near ion Larmor radius scale

Magnetic reconnection occurs in smaller systems

Transition to ideal MHD regime at larger scales

Abstract

The effect of the finite ion Larmor radius on the dynamics of two counterstreaming weakly collisional plasma flows in a magnetic field of an arch configuration is considered. Hybrid numerical simulations show that in a system whose dimensions are close to the ion Larmor radius, more intense interaction dynamics are observed, the magnetic arch experiences a significant expansion with the formation of a region with an irregular character of magnetic lines, in which magnetic reconnection processes occur. In this case, the generation of a surface wave of the ion-cyclotron range is observed at the boundaries of the arch. An increase in the scale of the system compared to the ion Larmor radius leads to a transition to the ideal MHD regime, in which the evolution of the arch occurs much more slowly, and the development of instabilities is not observed.