Laser-Driven, Ion-Scale Magnetospheres in Laboratory Plasmas. I. Experimental Platform and First Results

TL;DR

This study demonstrates the creation and observation of ion-scale magnetospheres in laboratory plasmas using laser-driven experiments, providing insights into kinetic-scale plasma physics relevant to planetary magnetospheres.

Contribution

The paper introduces a novel experimental platform for generating ion-scale magnetospheres in the lab and compares results with PIC simulations to validate kinetic plasma models.

Findings

Formation of kinetic-scale magnetopause structures at higher dipole moments

Magnetopause locations match pressure balance predictions

High-resolution magnetic field measurements reveal current structures

Abstract

Magnetospheres are a ubiquitous feature of magnetized bodies embedded in a plasma flow. While large planetary magnetospheres have been studied for decades by spacecraft, ion-scale "mini" magnetospheres can provide a unique environment to study kinetic-scale, collisionless plasma physics in the laboratory to help validate models of larger systems. In this work, we present preliminary experiments of ion-scale magnetospheres performed on a unique high-repetition-rate platform developed for the Large Plasma Device (LAPD) at UCLA. The experiments utilize a high-repetition-rate laser to drive a fast plasma flow into a pulsed dipole magnetic field embedded in a uniform magnetized background plasma. 2D maps of magnetic field with high spatial and temporal resolution are measured with magnetic flux probes to examine the evolution of magnetosphere and current density structures for a range of dipole and upstream parameters. The results are further compared to 2D PIC simulations to identify key observational signatures of the kinetic-scale structures and dynamics of the laser-driven plasma. We find that distinct 2D kinetic-scale magnetopause and diamagnetic current structures are formed at higher dipole moments, and their locations are consistent with predictions based on pressure balances and energy conservation.