INVESTIGATION OF EROSION IN ANODE LAYER THRUSTER AND ELABORATION HIGH LIFE DESIGN SCHEME

the surface, j density of ion flow on the surface. Lifetime is one of the most significant parameters determining perspectives of electric thrusters flight It is obviously, that increasing of the lifetime may use. As well as in another types of thrusters, the be achieved in the following ways: erosion of discharge chamber walls is the main factor increasing wall thickness; limiting lifetime of anode layer thrusterls (ALT). decreasing of value "s" by using more lower energy Therefore investigation of this processes is ions (low discharge voltage) and special resistive wall principally important for development of high materials and proper propellant; lifetime thrusters. In this article a results of decreasing of the ion flow on the surfaces of the experimental study erosion processes and discharge chamber walls. investigation new ALT scheme with low erosion are presented. Increasing of wall thickness require modifications in thruster structure, which, as a rule, can not be Nomenclature made without deviation of it's parameters. Significant sputtering mass leads to a possibility of a dimension of thruster harmful film deposition on another parts of the discharge chamber thruster or spacecraft. Propellant and ion energy (discharge voltage) are determined by required a value of erosion thruster efficiency and specific impulse. That is why variation of these parameters can not be widely used a' erosion rate of discharge for creation of high lifetime thruster. So that, the chamber walls most attractive ways are: application of a resistive materials, 1 discharge chamber length decreasing the part of ion beam impinging the chamber walls. Vd discharge voltage Carbon materials are the most resistive among Id discharge current available for chamber walls ), and so that these materials are the most attractive for application in ) thruster efficiency high lite time thrusters. F thrust Since possibilities of variation of ion flow on the walls were not clear, some special investigation had Isp specific impulse been carried out to determine the features of erosion processes and to find a way of it's decreasing (4 . T lifetime Investigations of both ALT modifications singlejion current density and doublestage thrusters have shown, that the laws of erosion are similar in both types of ALT. So Investigation of erosion processes that it is possible to find cut common ways to elaborate high life time thrusters. Investigations (1) have shown, that a cause of erosion is sputtering of walls material by accelerated Fig. 1 shows design scheme of discharge chamber ions. Using the known law of this process (), erosion of experimental models had been used (for rate "a"' can be expressed as double-stage thruster this is a scheme of second a a' s x j second stage stage of ion acceleration). Erosion rate s coefficient depending on ion atomic weight and "a'"was determined as ratio of screen wear value "a" energy, wall material, and incidence angle relative to to duration of tests "t" in steady state operation mode a'-a/t.