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This paper proposes increasing the width of the discharge channel to improve the specific impulse of Hall thrusters. In our study, we significantly increased the achievable channel width by optimizing the magnetic circuit topology, and the design freedom of the Hall thruster was improved. A prototype of a wide-channel high-specific-impulse Hall thruster was designed and experimentally verified. The effects of channel width on the discharge process and the characteristics of an aft-loaded magnetic field Hall thruster were investigated. The high-intensity luminous region did not diffuse radially with an increase in the channel width, and the plasma was always concentrated near the channel centerline. A wider channel is more conducive for improving the propellant utilization efficiency, thereby effectively improving the specific impulse of the Hall thruster. By optimizing the discharge channel width, the upper limit of the discharge voltage was increased, and the maximum specific impulse was increased from 3170 to 3794 s, a relative improvement of 20%. The effect of the specific impulse improvement at the same discharge voltage was analyzed and discussed. The results of this study are significant for the design of high-specific-impulse Hall thrusters. [ABSTRACT FROM AUTHOR]

A type of Hall thruster without wall losses is designed by adding two permanent magnet rings in the magnetic circuit. The maximum strength of the magnetic field is set outside the channel. Discharge without wall losses is achieved by pushing down the magnetic field and adjusting the channel accordingly. The feasibility of the Hall thrusters without wall losses is verified via a numerical simulation. The simulation results show that the ionization region is located in the discharge channel and the acceleration region is outside the channel, which decreases the energy and flux of ions and electrons spattering on the wall. The power deposition on the channel walls can be reduced by approximately 30 times. [ABSTRACT FROM AUTHOR]