Anomalous Heating and Plasmoid Formation in a Driven Magnetic Reconnection Experiment

TL;DR

This study investigates magnetic reconnection in a laboratory plasma experiment, revealing high temperatures, plasmoid formation, and evidence of two-fluid effects through advanced diagnostics.

Contribution

It provides detailed measurements of reconnection dynamics, energy partition, and plasmoid formation in a controlled experimental setup, highlighting non-classical dissipation mechanisms.

Findings

High electron and ion temperatures exceeding classical predictions

Repeated plasmoid formation and ejection observed

Evidence of two-fluid effects in magnetic reconnection

Abstract

We present a detailed study of magnetic reconnection in a quasi-two-dimensional pulsed-power driven laboratory experiment. Oppositely directed magnetic fields $(B=3$ T), advected by supersonic, sub-Alfv\'enic carbon plasma flows $(V_{in}=50$ km/s), are brought together and mutually annihilate inside a thin current layer ($\delta=0.6$ mm). Temporally and spatially resolved optical diagnostics, including interferometry, Faraday rotation imaging and Thomson scattering, allow us to determine the structure and dynamics of this layer, the nature of the inflows and outflows and the detailed energy partition during the reconnection process. We measure high electron and ion temperatures $(T_e=100$ eV, $T_i=600$ eV), far in excess of what can be attributed to classical (Spitzer) resistive and viscous dissipation. We observe the repeated formation and ejection of plasmoids, which we interpret as evidence of two-fluid effects in our experiment.