In this paper the behavior of the integral parameters of the Hall thruster (thrust, specific thrust impulse) in two stable discharge modes were experimentally investigated. This modes significantly different from each other in anode efficiency. The studies were carried out on a laboratory model of Hall thruster with the external discharge zone with the middle-line diameter equal to 77 mm. The discharge voltage was in the range of 500-900 V and a gas flow rate was from 2.0 to 5 mg/s. The most striking differences between the discharge modes are the shape of the plasma plume and the value of the discharge current at practically identical input parameters of operation (gas flow rate, discharge voltage, magnetic field). It is shown that in the entire studied range of input parameters during the transition from the optimal mode (in terms of the efficiency) to the suboptimal mode the main integral characteristics of the thruster suddenly change: the discharge current increases by 10-30% with the simultaneous relative drop of thrust by 5-15% and efficiency by 20-40%. A detailed study of the structure of the anode efficiency showed that when the transition between modes occurs the electron current efficiency (the ratio of the ion current to the discharge current) abruptly changes, that is, the electronic conductivity in the discharge channel of the thruster changes too.
Параметрическое исследование двух устойчивых форм горения разряда в холловском двигателе