Optical radiation of the plasma flow in an arcjet thruster

摘要

The electrothermal Arcjet are used in spacecraft orientation systems. A design feature of the Arcjet chamber is an enclosed volume containing a plasma streamlined by a stream of cold gas. The methods of emission spectroscopy make it possible to estimate the kinetic parameters of the working gas of the engine, the emission of electrodes, the velocity of the gas jet, and, in some cases, the concentration of the components. One of the most important parameters is the components temperature of the plasma gas forming. The temperature of the argon working gas in the Arcjet chamber was found in the approximation of partial local thermal equilibrium. The temperature value made it possible to determine the effective argon flow rate and the corresponding speed of sound and made it possible to explain the experimental results of the found oscillation frequency of the arc voltage of the discharge chamber in the Helmholtz resonator mode near f_H = 6.25 kHz. It is shown that the length of the discharge chamber in the approximation of a partially-open resonator can be decisive when finding the resonator's own oscillations.