Confined discharge plasma sources for Z-pinch experiments

The authors have investigated Z-pinch implosion on the NRL Gamble II generator using metallic sources of sodium and aluminum and nonmetallic sources of sodium (NaF), magnesium (MgF/sub 2/), and aluminum (Al/sub 2/O/sub 3/). For 1-MA driving currents, peak K-shell radiated power of about 100 GW and energies of about 1.5 kJ have been obtained with both pure aluminum and NaF implosions. The aluminum results are comparable to those in previous Gamble II experiments with aluminum wire arrays. The work has been motivated by the need for a sodium source for Na/Ne X-ray laser experiments. Confined discharge sources have been used to generate tens of gigawatts in the Na and He- alpha pump line, and fluorescence of the neon has been observed. The effects of nozzle shape and size, chamber diameter, amount of fuse material, and confined discharge current have been investigated in Gamble II implosion experiments. The studies indicate that confined discharge sources are capable of supplying significantly more material than required for implosions at the 1-MA level, so that this technique could be extended to higher current generators.<>