Coaxial Microwave Plasmas in Argon: Radial Contraction, Self-Organization and more Exotic Phenomena

TL;DR

This study investigates coaxial microwave argon plasmas, revealing phenomena such as radial contraction, self-organization, and exotic patterns, using optical and laser diagnostics to analyze plasma behavior at different pressures.

Contribution

It introduces a novel coaxial microwave plasma setup capable of observing self-organized patterns and exotic phenomena in argon plasmas at varying pressures.

Findings

Observation of radial contraction and self-organized finger-like structures.

Identification of plasma stability limits at different pressures.

Detection of exotic plasma phenomena beyond traditional glow discharge behaviors.

Abstract

A coaxial microwave plasma setup was designed for investigation by optical and laser diagnostics. The plasma is sustained by two microwave power sources located at both ends of a coaxial line. This allows generating an axially homogeneous glow discharge at low pressure. For increasing pressures, this glow-like mode is found to be unstable and various self-organized patterns are observed including finger-like structures which can be sustained after the visible end of the plasma column.