Magnetohydrodynamic structure of a plasmoid in fast reconnection in low-beta plasmas: Shock-shock interactions

TL;DR

This study uses high-resolution 2D MHD simulations to analyze the shock structures within plasmoids during magnetic reconnection in low-beta plasmas, revealing complex shock interactions and features relevant to astrophysical jets.

Contribution

It provides detailed insights into shock-shock interactions and new shock structures inside plasmoids, advancing understanding of reconnection dynamics in low-beta plasmas.

Findings

Contact discontinuities from triple-shock intersections separate fluids of different origins.

Shock-diamonds inside the plasmoid decelerate supersonic flows.

Discovery of new shock-diamonds and a slow expansion fan inside the Petschek outflow.

Abstract

The shock structure of a plasmoid in magnetic reconnection in low-beta plasmas is investigated by two-dimensional magnetohydrodynamic simulations. Using a high-accuracy code with unprecedented resolution, shocks, discontinuities, and their intersections are resolved and clarified. Contact discontinuities emanate from triple-shock intersection points, separating fluids of different origins. Shock-diamonds inside the plasmoid appear to decelerate a supersonic flow. New shock-diamonds and a slow expansion fan are found inside the Petschek outflow. A sufficient condition for the new shock-diamonds and the relevance to astrophysical jets are discussed.