Physical properties of dense plasma produced by XeCl excimer laser in high-pressure argon gases

When XeCl excimer laser light was focused in high-pressure Ar gas up to 150 tm, a hot and dense plasma developed not only backward but also forward. T he physical properties of the plasma produced by an ultraviolet laser in hi gh-pressure gases have not been studied yet except for the mechanism involv ed in its development. Interferometric and spectroscopic measurements were carried out. Electron density was measured using a Mach-Zehnder interferome ter When laser intensity was 2 x 10(11) W/cm(2) at the focal spot, electron density was proportional to the pressure and a fully ionized state was alm ost achieved up to 150 atm. Dense plasma with electron density of the order of 10(27) m(-3) was obtained. Electron density was highest at the focal sp ot End the; forward electron density was higher than the backward one. Elec tron temperature was estimated from continuous:intensities. Electron temper ature at the focal spot of the order of 10(5) K was obtained. The electron temperature distribution differed from the electron density distribution, i n which the backward electron temperature Was higher than the forward one.