A critical state model for estimating the parameters of explosive emission plasmas

Abstract

The parameters of the cathode spot plasma produced by explosive electron emission pulses have been estimated from the critical state properties for various materials. The kinetic energy of the cathode plasma flare has been estimated as 100 Tcr, where Tcr is the critical temperature of the cathode material. Based on a Saha-like equation and a two-temperature simulation of the explosion of a liquid-metal microjet, an estimation formula for the average ion charge has been derived, Zav = 1 + Tcr/eV, which fits the available experimental data. This has made it possible to explain the linear relationship between average charge and kinetic energy obtained experimentally for the cathode plasma ions. Using this formula, the previously derived expression for the plasma momentum per transferred charge μ has been simplified to become μ ∼5 (Mi/Mp)1/2 g cm/(s C), where Mi/Mp is the ion-to-proton mass ratio.