Effect of preionization on the implosion dynamics of single and double argon gas puffs

Experiments on the implosion of both single and double argon gas puffs were carried out in the IMRI-4 (t(fr) = 1.1 mu s and I-m = 350 kA) and GIT-4 (t (fr) = 0.12 mu s and I-m = 1.7 MA) current generators. Three different sour ces of gas-puff preionization were used: (i) UV spark radiation, (ii) a cyl indrical magnetron discharge in the crossed E x B fields, and (iii) a plana r magnetron discharge in the crossed E x B fields. With the use of an optic al streak camera, for all three methods of preionization, conditions are fo und under which the stratification of the current sheet occurs during the i mplosion of the gas puff. Experimental data show that the dynamics of the g as-puff implosion depends on the preionization method. The use of magnetron preionization results in suppression of the instabilities excited during t he gas-puff implosion and allows the obtaining of stable plasma parameters in the final stage of implosion. It is shown that, in a single gas puff, a plasma column with an initial radius of 30 mm can be uniformly compressed t o a stable plasma cylinder with a radius less than 2 mm.