Plasma losses from mirror trap, initiated by microwave radiation under electron cyclotron resonance conditions

TL;DR

This study investigates plasma losses in a mirror trap caused by microwave radiation under electron cyclotron resonance conditions, demonstrating how resonance proximity influences discharge extinction and particle precipitation.

Contribution

It provides experimental validation of particle precipitation effects due to ECR interactions and correlates extinction power with resonance positioning in a magnetic trap.

Findings

Discharge extinction occurs near gas breakdown threshold with increasing radiation power.

Extinction power decreases as the ECR cross section approaches the magnetic plug.

Experimental results align with quasilinear diffusion theory estimates.

Abstract

Plasma of a stationary ECR discharge sustained by gyrotron radiation at a frequency of 24 GHz and a power of up to 600 W in a mirror magnetic trap was studied. At pressures near the gas breakdown threshold, the extinction effect of an electron-cyclotron discharge is observed with increasing radiation power. When the cyclotron resonance cross section approaches the magnetic plug, the power threshold corresponding to the discharge extinction decreases. These experimental results confirm the presence of the effect of particles precipitation from the trap as a result of electron-cyclotron resonance interaction with gyrotron radiation. The experimental scaling of the extinction power dependence on the position of the ECR cross section in a magnetic trap corresponds to the results of the estimates on the basis of the theory of particle precipitation in the quasilinear diffusion regime.