High-Spatial-Resolution Multichannel Thomson Scattering Measurements for Atmospheric Pressure Microdischarge

High-spatial-resolution multichannel Thomson scattering measurement scheme is applied to the diagnostics of a microplasma produced between two knife-edge electrodes separated by a 100 µm microgap and driven by 2.45 GHz microwave. The method provides spatial profile of electron density, electron temperature, and gas temperature simultaneously in a single measurement, with a spatial resolution of ∼25 µm; the gas temperature is derived from the spectrum of rotational Raman scattering caused by molecules contained in the discharge gas. Measurements are carried out for discharges with air and He/N 2 (5%) mixture gas at atmospheric pressure and the differences in the basic plasma parameters are discussed.