Characteristics of a Sheath with Secondary Electron Emission in the Double Walls of a Hall Thruster

Abstract

In order to investigate the effects of secondary electrons, which are emitted from the wall, on the performance of a thruster, a one-dimensional fluid model of the plasma sheath in double walls is applied to study the characteristics of a magnetized sheath. The effects of secondary electron emission (SEE) coefficients and trapping coefficients, as well as magnetic field, on the structure of the plasma sheath are investigated. The results show that sheath potential and wall potential rise with the increment of SEE coefficient and trapping coefficient which results in a reduced sheath thickness. In addition, magnetic field strength will influence the sheath potential distributions.

Effect of low-frequency oscillation on performance of Hall thrusters

“…Then, assuming a symmetric plume, the total ion current can be calculated using formula (1). And the edge of the region comprising 90% of the total ion current is taken as the boundary of the plume divergence half-angle, it can be calculated using formula (2).…”

“…Hall thrusters have been widely applied in attitude control, position keeping, orbital transfer of satellites, and other space propulsion missions due to the advantages of their simple structure, moderate specific impulse, high efficiency, etc [1,2]. During the discharge of a Hall thruster, a 20-40 kHz low-frequency oscillation (often called the breathing mode oscillation) occurs [3][4][5][6].…”

A method to measure the in situ magnetic field in a Hall thruster based on the Faraday rotation effect

“…Hall thrusters have small thrust, long life, moderate specific impulse, and other characteristics, which can reduce satellite payload and launch costs, extend the life of satellites, and shorten interplanetary mission time. Therefore, they are used to maintain the satellite's north-south position in orbital transfer, deep space exploration, and other space missions [1][2][3]. Hall thrusters enable electron constraint and ion acceleration by their orthogonal electric and magnetic field.…”

Characteristics of wall sheath and secondary electron emission under different electron temperatures in a Hall thruster

“…[10][11][12][13] In addition, the institute established a 1D fluid sheath model, analyzing the influence of the secondary electron emission coefficient on plasma sheath properties in Hall thruster channels numerically. [14][15][16] Fluid simulation, hybrid simulation and particle simulation are often used to numerically model the plasma sheath in Hall thrusters. Although the computing efficiency of fluid simulations is higher, electrons are assumed to be in the Maxwell distribution in the fluid model.…”