Investigation of dense argon plasmas in a simple capillary discharge

In a simple capillary discharge with charging voltages as high as 35 kV dense argon plasmas were produced and studied displaying reproduceable emission of the 3p-3s lines of the Ar IX ion. The obtained electron densities did not exceed 2 x 1018 cm-3, and no clear lasing was observed. Pinhole spectra and time resolved measurements of the electron density indicate that the compression of the plasma was too weak because of the slow current rise. Comparison with a faster discharge indicates that a minimum current rise of 0.6 x 1012 A/s is needed to obtain sufficient compression and thus measurable gain on Ar IX 3p-3s lines. (orig.)