Plasma probing with a table-top soft x-ray laser

Summary form only given. Due to their short wavelength, high brightness, and good spatial coherence soft X-ray lasers are excellent sources for the diagnostics of dense plasmas. We report the demonstration of plasma imaging and interferometry using a very compact table-top soft X-ray laser. A capillary discharge pumped 46.9 nm laser was used to obtain a sequence of high resolution shadowgrams of the plasma of a microcapillary discharge (380 /spl mu/m diameter, 8 mm long evacuated channel in polyacetal excited by a /spl sim/1.5 kA peak amplitude current pulse of 155 ns duration). The plasma was illuminated on-axis with the soft X-ray laser, and was imaged with 24/spl times/ magnification into an MCP/CCD detector using a 60 cm radius of curvature concave mirror coated with an iridium film. The plasma is observed to rapidly evolve from a nonuniform plasma into a remarkably uniform plasma column with minimum density on axis. These measured plasma characteristics confirm the excellent properties of these discharges as waveguides for laser radiation.