Experimental Evidence of Plasmoids in High-$\beta$ Magnetic Reconnection

TL;DR

This paper presents experimental evidence of plasmoid formation in high-$eta$ magnetic reconnection, a regime previously lacking direct observations, advancing understanding of plasma physics in space and astrophysical environments.

Contribution

The study provides the first strong experimental evidence of plasmoids in high-$eta$ reconnection, confirming theoretical predictions in this less-explored regime.

Findings

Observation of plasmoid formation in high-$eta$ reconnection

Evidence of plasmoid dynamics in laser-driven experiments

Supports theories predicting plasmoids in high-$eta$ environments

Abstract

Magnetic reconnection is a ubiquitous and fundamental process in plasmas by which magnetic fields change their topology and release magnetic energy. Despite decades of research, the physics governing the reconnection process in many parameter regimes remains controversial. Contemporary reconnection theories predict that long, narrow current sheets are susceptible to the tearing instability and split into isolated magnetic islands (or plasmoids), resulting in an enhanced reconnection rate. While several experimental observations of plasmoids in the regime of low- to intermediate-$\beta$ (where $\beta$ is the ratio of plasma thermal pressure to magnetic pressure) have been made, there is a relative lack of experimental evidence for plasmoids in the high-$\beta$ reconnection environments which are typical in many space and astrophysical contexts. Here, we report the observation of strong experimental evidence for plasmoid formation and dynamics in laser-driven high-$\beta$ reconnection experiments.