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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]

In this paper, a type of magnetically insulated anode structure is proposed for the design of a low-power cylindrical Hall thruster. The magnetic field distribution in the channel is guided by the magnetically insulated anode, altering the intersection status of the magnetic field line passing through the anode and wall. Experimental and simulation results show that a high potential is formed near the wall by the magnetically insulated anode. As the ionization moves towards the outlet, the energy and flux of the ions bombarding the channel wall can be reduced effectively. Due to the reduction in the bombardment of the wall from high-energy ions, the thrust and specific impulse greatly increase compared with those of the non-magnetically insulated anode. For anode mass flow rates of 0.3 and 0.35 mg s−1 and discharge voltages in the 100–200 V range, the thrust can be increased by more than 33% and the anode efficiency can be improved by more than 7%. Meanwhile, the length of the sputtering area is clearly reduced. The starting position of the sputtering area is in front of the magnetic pole, which can effectively prolong the service life of the thruster. [ABSTRACT FROM AUTHOR]

It has been recognized that the application of magnetic shielding technology deteriorates the plume divergence efficiency of a Hall thruster. To try to alleviate this effect, three magnetic shielding configurations with different inclination directions of the lines of force in the strong magnetic field region are designed via the introduction of a peripheral coil surrounding the thruster body, and their influence on the performance and plume divergence are experimentally evaluated in this study. The measured results show that the performance and plume distribution vary significantly with the change in the inclination direction of the lines of force. Particularly, different to the unshielded Hall thruster that exhibits the best performance and minimal divergence when the strong magnetic field lines are non-inclined (perpendicular to the thruster axis), the magnetically shielded Hall thruster has the largest thrust and the smallest divergence angle when the strong magnetic field lines are inclined inward. Further theoretical research indicates that this is mainly due to the change in the ion acceleration process under the magnetic shielding discharge. This study is significant and instructive for the optimized design of magnetically shielded Hall thrusters. [ABSTRACT FROM AUTHOR]