THE CONTINUUM ABSORPTION OF ARGON, KRYPTON AND XENON DENSE-PLASMAS PRODUCED IN FLASHLAMPS

The optical thickness of dense plasma, created in linear flashtubes filled with noble gases, is measured over the wavelength range 466-780 nm using a cw laser beam. The electron density and temperature radial profiles of the plasma are determined by spectroscopic methods, infrared laser interferometry and local thermodynamic equilibrium equations. Knowing those profiles, the absorption coefficients and consequently the xi(fb) factors are deduced from optical thickness measurements. These factors are compared with theoretical values of Hofsaess and with previously published experimental results. The dependence of xi(fb) on the wavelength and the plasma parameters (electron density in the range 7 x 10(17)-1.7 x 10(18) cm(-3), temperature between 10900 and 17000 K) is discussed. The effect of the interparticle interaction on the absorption in our dense plasmas is only sensitive to the shift of the photoionization thresholds of atoms.