Analysis of x-ray spectra obtained in foam Z-pinch experiments

Abstract

Time and space resolved measurements of visible-light and soft x-ray emission from foam z-pinch plasmas and implosions Rev.Foam Z-pinch experiments have recently been performed on SATURN to study issues associated with the initiation, acceleration, and stagnation phases of the pinch. Time-integrated x-ray crystal spectra have been recorded from experiments with 5 mg/cc Si aerogel loads and 10 mg/cc agar loads. In this article, we describe results from collisional-radiative equilibrium calculations performed to analyze the Si, Na, and S K-shell emission observed in the spectra. Particular attention is paid to density and opacity effects on intensity ratios involving He ␣ , He intercombination, and Li-like satellite lines.

The physics of fastZpinches

“…In a plasma with incompletely stripped ions, the tail of the electron distribution function experiences losses caused by excitation and ionization events; therefore, the tail may become depleted, affecting the rate of excitation and the radiation intensity (see, for example, Clark, Davis, and Cochran, 1986;DeGroot et al, 1997a). An example of an analysis of experimental data on x-ray spectra from implosions of the foam loads on the Saturn device, with nonequilibrium effects included, can be found in MacFarlane et al (1997). In quasistatic pinches, an important channel of heat loss is an enthalpy flow to the electrodes related to the pinch current (Haines, 1960).…”

The physics of fast Z pinches

“…As in a plasma with non-fully stripped ions the tail of the electron distribution function experiences losses caused by excitation and ionization events, the tail may get depleted, affecting the rate of the excitation and the radiation intensity (DeGroot, 1997). An example of the analysis of the experimental data on x-ray spectra fiom implosions of the foam loads on the Saturn device, with non-equilibrium effects included, can be found in MacFarlane et al (1997).…”