Density effects on the spectral emission of a high temperature argon plasma

In order to explain the detailed features of radiation spectra obtained from dense argon plasmas, an ionization-radiation model for argon has been constructed which calculates time-integrated spectra as a function of plasma temperature, density and size. The model describes a plasma in collisional-radiative equilibrium by solving the time-dependent atomic rate equations for ground state and selected excited state populations of argon coupled with a probability-of-escape radiation transport scheme for both bound-bound and bound-free photons. Results are presented which illustrate basic changes in the X-ray spectra of an argon plasma as density is increased, in particular, relative intensities of resonance, satellite and intercombination lines as well as the free-bound continuum. In addition, temperature and density profiles from 1-D MHD calculations characterizing the peak emission from argon puffed-gas plasmas (approximately 1019 ions/cm3) and argon-seeded laser-imploded microballoons (approximately 1022 ions/cm3) are post-processed using the model and the resulting spectra are discussed. (author)