Observation of particle acceleration in laboratory magnetosphere

TL;DR

This paper reports the first laboratory observation of a radiation belt created in a magnetosphere device, demonstrating particle acceleration mechanisms similar to planetary radiation belts through spectroscopic measurements.

Contribution

It provides experimental evidence of particle acceleration and anisotropic heating in a laboratory magnetosphere, confirming betatron acceleration as a key process.

Findings

Observation of a laboratory radiation belt in RT-1 device

Detection of ion temperature anisotropy indicating betatron acceleration

Energy balance model explains ion temperature profile

Abstract

The self-organization of magnetospheric plasma is brought about by inward diffusion of magnetized particles. Not only creating a density gradient toward the center of a dipole magnetic field, the inward diffusion also accelerates particles and provides a planetary radiation belt with high energy particles. Here, we report the first experimental observation of a 'laboratory radiation belt' created in the Ring Trap 1 (RT-1) device. By spectroscopic measurement, we found an appreciable anisotropy in the ion temperature, proving the betatron acceleration mechanism which heats particles in the perpendicular direction with respect to the magnetic field when particles move inward. The energy balance model including the heating mechanism explains the observed ion temperature profile.