The influence of spatial inhomogeneity of pulsed capillary discharge on the gas dynamics of multicomponent plasma

Abstract

The results of experimental research of a pulsed capillary discharge with an evaporating wall in the power density range of qs = 10 − 100 kW/cm2 obtained by using independent methods of diagnostics, including optical spectroscopy, the ballistic pendulum method, and direct measurement of pressure inside the capillary are presented. The analysis of experimental results, carried out with the help of a two-zone model of a capillary discharge, revealed the decisive influence of the discharge spatial inhomogeneity on the gas dynamics of a multicomponent plasma, which turns out to be substantially different in the high-temperature paraxial and low-temperature peripheral discharge zones. It is shown that the gas dynamics of the paraxial discharge zone corresponds to the regime of the ideal expendable nozzle with good accuracy, and the paraxial zone itself provides the main contribution to the creation of the jet momentum, in spite of the fact that more than 80% of the evaporated substance is carried away from the capillary through the peripheral zone. It is shown that high losses in the plasma jet stagnation pressure, reaching up to 80% relative to the pressure measured inside the capillary, belong to the peripheral discharge zone, in which the density and velocity, respectively, are two orders of magnitude higher and an order of magnitude lower than the corresponding values in the paraxial zone.