Anomalous plasma acceleration in colliding high-power laser-produced plasmas

TL;DR

This paper presents an experimental study of plasma acceleration during magnetic reconnection in laser-produced plasmas, revealing unexpected flow behavior possibly driven by magnetic tension forces.

Contribution

It introduces a novel experimental platform for studying magnetic reconnection with detailed plasma and magnetic field measurements, highlighting new acceleration mechanisms.

Findings

Plasma flow accelerates toward high-density regions contrary to pressure gradient expectations.

Magnetic reconnection involves the interaction of magnetic field loops generated by Biermann battery effect.

Magnetic tension force may significantly contribute to plasma acceleration during reconnection.

Abstract

We developed an experimental platform for studying magnetic reconnection in an external magnetic field with simultaneous measurements of plasma imaging, flow velocity, and magnetic-field variation. Here, we investigate the stagnation and acceleration in counter-streaming plasmas generated by high-power laser beams. A plasma flow perpendicular to the initial flow directions is measured with laser Thomson scattering. The flow is, interestingly, accelerated toward the high-density region, which is opposite to the direction of the acceleration by pressure gradients. This acceleration is possibly interpreted by the interaction of two magnetic field loops initially generated by Biermann battery effect, resulting in a magnetic reconnection forming a single field loop and additional acceleration by a magnetic tension force.