ELECTRON-TEMPERATURE AND DENSITY-MEASUREMENTS IN LASER-PRODUCED LARGE-SCALE-LENGTH GAS-BAG PLASMAS BY X-RAY SPECTROSCOPY

We present temporally and spatially resolved measurements of the K-she ll emission from argon and chlorine dopants in laser-produced mm-size gas-bag plasmas. Particularly useful for the diagnostics of these plas mas are the line intensity ratios of the He- and H-like resonance line s to their respective Li- and He-like dielectronic satellite transitio ns. By Abel inverting the experimental spectra and applying time-depen dent collisional-radiative modeling, local electron temperatures, and densities are deduced. About 0.4 ns after the beginning of the laser h eating, we observe a homogeneous plasma center which heats steadily un til the end of the heating pulse. Although the heating is slower than predicted by hydrodynamic simulations, the measured peak electron temp erature of T-e = 3 keV for neopentane-filled gas bags is in good agree ment with the hydrodynamic simulations. In addition, the electron dens ities inferred from the line intensity ratio of the intercombination t o the resonance line of heliumlike argon are consistent with 10(21) cm (-3) as expected from the initial gas fill density. Further gas fill d ensities have been investigated, and in agreement with simulations we find lower temperatures for lower gas densities.