Investigation of a short-wavelength laser plasma of a gas-liner pinch discharge

We studied the axial homogeneity of a gas-liner pinch plasma where amplification of line radiation at short wavelengths had been reported in an earlier study. For this purpose we measured temporally and axially resolved the Stark-broadened n=5 to n=4 transitions in F VII. From the linewidth electron densities are deduced employing spectral line shape calculations which are tested by Thomson scattering. We observe significant plasma inhomogeneities produced by Rayleigh-Taylor instabilities. Density gradients of δne/ne∼3 along the plasma axis on a scale length of z<1 mm were found. They arise when compressing large amounts of a heavy gas (fluorine) of 5 endash 10% total gas density in the discharge with a hydrogen pusher for short-wavelength laser studies. Reducing their amount to about 1% of the total gas density results in homogeneous discharges. In this case no amplification can be observed. copyright 1997 The American Physical Society