Characterization of Laser-Induced Plasma in Nitrogen

We perform optical and spectroscopic studies of laser-induced plasmas (LIPs) in nitrogen under different experimental conditions. Our aim to determine the characteristics of LIPs associated with laser-ignition applications. The plasma is generated in nitrogen with the help of a 10 Hz and ~ 7 ns Nd:YAG laser operating at 532 nm. We investigate the effects of nitrogen pressure and laser irradiance on the electron temperature and laser-energy-absorption rate by LIPs. The electron temperatures are found almost unchanged from 2.85 to 2.98 eV. The laser-energy-absorption rate by the LIP increases with increase in the laser-pulse energy and nitrogen pressure. Consequently, the laser irradiance and increasing nitrogen pressure improve the plasma-particle density and plasma energy and thus improve the laser-ignition probability.