We report the generation of plasma columns in gas-filled capillary channels using discharge excitation powers that exceed those of previous studies by one to two orders of magnitude. Current pulses up to 200 kA and 10–90 % rise time of ∼10 ns (current increase rate $\sim 1.5\times {10}^{13}\mathrm{A}/\mathrm{s})$ were utilized to excite plasmas in 3.3 and 4 mm diameter channels. Time resolved soft-x-ray spectra and pinhole images of the plasma were obtained. The experimental data and its comparison with model computations suggest that dense argon plasma columns 300 μm in diameter with electron temperatures >250 eV have been obtained. These characteristics make these plasmas of interest for extending discharge-pumped lasers to shorter wavelengths.

• Received 4 June 2001

DOI:https://doi.org/10.1103/PhysRevE.65.026404