Effects of the ionization degree on the initial-phase current distribution of a Z-pinch discharge

In the study on how in the Z-pinch discharge the current density distribution following the Z-discharge is influenced by the initial ionization degree of the sealed gas, simulation of the He partial ionization Z-pinch plasma was made at sealed gas pressure 37 m Torr and initial ionization degree 0.01 -- 1.0 %. (1) With the high initial ionization degree (>= 1 %), the plasma resistance in Z-discharge initiation is small so that the current density first becomes a maximum near the discharge tube wall. (2) With the low initial ionization degree (>= 0.1 %), the plasma resistance is large due to collision between electrons and neutral particles so that the current is immediately distributed uniformly in the discharge tube. (Mori, K.)