Merkurev D.V., Kalyazin V.G., Kim V.P., Shilov E.A., Zakharchenko V.S.

merckuriev.denis@yandex.ru, riame4@sokol.ru

This paper presents an analysis of the effect of pressure in a vacuum chamber on the accuracy of parameter measurement and the operation of a stationary plasma thruster (SPT). One of the most important factors affecting the deviation of the measured values of the thruster parameters from the expected under the operation of thrusters in space is the presence in the vacuum chamber of a “background” atmosphere, mainly consisting of particles of “used” SPT propellant, from which to the thruster a "back" flow occurs, which increases the actual consumption of the propellant through the accelerator channel of the thruster. Moreover, the influence of this atmosphere is not limited only to an increase in the particles of the propellant flow from the chamber to the thruster, since the input of propellant particles and the increased concentration of particles at the exit plane of the accelerator channel compared to the full-scale conditions lead to a change in the distribution of the concentration of neutral propellant atoms, as well as the distributions of all other parameters in the SPT discharge, including the distribution of the electric field in the discharge volume. One of the possibilities to control the consequences of these changes is to measure the characteristics of the SPT beam at different pressures of the propellant particles in the vacuum chamber (for example, the distribution of current density and the distribution of average ion energies in the beam). Therefore, in this work, we measured the characteristics of the laboratory model SPT-40 of low power with an outer diameter of the accelerating channel of 40 mm at different pressures in the vacuum chamber.

The report presents the results and their analysis.

This work was financially supported by the Russian Science Foundation under grant No. 16-19-1042.

References

1          Kim V., Kozlov V., Popov G., Skrylnikov A., Umnitsyn L. Plasma Parameter Distribution Determination in SPT-70 Plume - paper IEPC-2003-107, 28^th International Electric Propulsion Conference, 17-21 March 2003, Toulouse, France.