Pair-loaded electron-only magnetic reconnection using laser-driven capacitor coils

TL;DR

This paper introduces a laser-driven laboratory setup to study how positrons affect magnetic reconnection, showing that injected electron-positron pairs significantly enhance reconnection rates and alter particle dynamics.

Contribution

It demonstrates the first simulation-based evidence that positron injection can modify magnetic reconnection in a controlled laboratory environment.

Findings

Injected pairs increase reconnection rate by ~8 times

Pairs broaden the diffusion region due to high energy and magnetization

Pairs can be confined for several picoseconds, enabling sustained interaction

Abstract

We propose and simulate a laboratory platform to study the effects of positrons in magnetic reconnection using laser-driven capacitor coils. Using particle-in-cell simulations, we show that externally injected MeV electron-positron pairs are trapped in the coil current sheet, significantly modifying the reconnection dynamics and particle acceleration. These pairs increase the reconnection rate by a factor of approximately 8, which Ohm's law decomposition reveals to be driven by the divergence of the generalized pressure tensor. Based on their high energy and magnetization, the pairs also substantially broaden the diffusion region. Particle tracking simulations in realistic coil magnetic fields further demonstrate that injected pairs can remain confined for several picoseconds, providing conditions for sustained interaction with the reconnection region. These results establish a near-term pathway to laboratory studies of positron-influenced reconnection, bridging high-energy-density experiments with pair-dominated astrophysical environments.