Thomson microwave scattering for electron number density diagnostics of miniature plasmas at low pressure

TL;DR

This paper introduces a new Thomson microwave scattering technique for measuring electron density in miniature low-pressure plasmas, validated against traditional methods, enabling accurate diagnostics in small plasma systems.

Contribution

A novel Thomson microwave scattering method for electron density diagnostics in miniature plasmas at low pressures, validated against established techniques.

Findings

Thomson microwave scattering measured electron density as 3.36×10^10 cm^-3.

Hairpin resonator measured electron density as 2.07×10^10 cm^-3.

Results show adequate agreement between the two measurement methods.

Abstract

This work proposes a novel method of Thomson microwave scattering for electron number density measurements of miniature plasmas at pressures < 10 Torr. This method is applied to determine electron number density in a positive column of glow discharge initiated at 5 Torr in air with a plasma column diameter of 3.4 mm. The Thomson Microwave Scattering(TMS) system measured the electron number density to be 3.36*10^10 cm^-3. The result obtained using the TMS system was validated against the measurements made using the well-known technique of microwave quarter-wave hairpin resonator. Measurements with the hairpin resonator yielded an electron number density of 2.07*10^10 cm^-3 providing adequate agreement with the TMS system.