Temperature and Electron Density Measurements of Laser-Induced Plasmas in Air at Elevated Pressures

ABSTRACT

We present time-resolved spectroscopic measurements of 1064-nm Nd:YAG laser-produced plasmas in air at pressures from 0.85 to 48.3 bar. We report temperatures and electron number densities of the plasmas at times between 200 ns and 3 µs after the plasma onset. Neutral atomic oxygen lines at 715 nm and 777 nm are used for temperature measurement through a Boltzmann analysis. Electron number density is measured using Stark broadened atomic hydrogen (H_α) line at 656 nm. We compare experimental results with modeling results obtained from using Taylor-Sedov blast-wave theory coupled with local thermal equilibrium composition calculations.