FAST-DISCHARGE EXCITATION OF HOT CAPILLARY PLASMAS FOR SOFT-X-RAY AMPLIFIERS

High-temperature (T(e) > 150 eV), small-diameter (approximately 200 mu m) plasma columns have been efficiently generated by very fast (13 ns rise time, 28 ns full width at half maximum) pulsed discharge excitati on of capillary channels filled with preionized gas. Discharges in arg on-filled capillaries at currents between 20 and 60 kA produced plasma s with Ar X-Ar XIV line emission, in which the degree of ionization wa s controlled by the magnitude of the current pulse. The characteristic s of these plasmas differ from those created by vacuum discharges in t he same capillaries and approach those necessary for soft-x-ray amplif ication in low-Z elements.