DYNAMICS OF A PINCH DISCHARGE IN CAPILLARIES

Results are presented from the one-dimensional MHD simulation of a cap illary discharge. Discharges with parameters close to those in experim ents in which the discharge plasma in the capillarics was used as a la sing media for soft X-ray emission are studied. Such effects as therma l conductivity, Joule heating of the plasma inside the channels, heati ng of the walls of the channels by the heat flow from the hot discharg e plasma, ablation of the wall material, and pinching of the plasma in side the channel are taken into account. For discharges in a channel f illed with a preionized gas, the simulations predict that, at the mome nt when the converging shock wave reaches the channel axis, as a resul t of gas dynamic cumulation, a high-density hot kernel is formed near the axis. We assume the conclusion is drawn that the amplification of the radiation observed in experiments can be caused by the formation o f similar structures. When the discharge develops in an initially evac uated channel, after a short transient process, the plasma is in a dyn amic and thermal equilibrium with a relatively low temperature. The pr oblem of the production of hydrogen C5+ ions in a relatively cool disc harge plasma formed in an initially evacuated channel is discussed wit h runaway electrons taken into account.