Study on the Relation Between Discharge Voltage and Magnetic Field Topography in a Hall Thruster Discharge Channel

Abstract

The relation between magnetic field topography and operating voltage is investigated in a 1kW Hall thruster discharge channel in order to focus the ion beam effectively and optimize the performance. The curvature of magnetic field line (α) is introduced to characterize the differences of topologies. The optimized magnetic field distribution under each operating voltage is obtained by experiment. Through the curvature transformation, we find that the area of (α > 1) in the channel gradually decreases with the increase of the operating voltage. In response to the results above, two dimensional plasma flows are simulated employing Particle-in-Cell method. The distributions of the electric potential, ion density and ion radial velocity are calculated to understand the important influence of the relation above on ion beam focusing. The numerical results indicate that magnetic field curvature and thermal electric field control the ion beam in the ionization and acceleration zone, respectively. The magnetic field topography and discharge voltage interact with each other and together form the focusing electric field. The ion radial mobility is suppressed effectively and the ion beam is focused to the channel centerline. In addition, for a given voltages, when the area of (α > 1) is larger than the optimal scope, the electric potential lines excessively bend to the anode causing ion over focus; contrarily, the electric potential lines will bend to the exit and defocus ions. All these results suggest the relation between magnetic field topography and discharge voltage is important to the ion radial flow control and performance optimization of the Hall thruster.

Particle‐in‐Cell Simulation for the Effect of Segmented Electrodes Near the Exit of an Aton‐Type Hall Thruster on Ion Focusing Acceleration

“…The geometrical scaling method [29] is also adopted here with the geometrical scaling factor 0.02. It is necessary to point out that this method has demonstrated its outstanding capability on improving the physics insight into the processes in Hall thrusters and on reproducing accurately well experimental data [17,30].…”

“…The simulated Hall thruster in this paper is a 1 kW ATON type which has an outer diameter of 71 mm, a channel width of 14 mm and a channel length of 30 mm [17], [18]]. Fig.…”

“…Although the effects of low-emissive segmented electrodes have been well documented, the reason of the plume widening is not fully understood. Moreover, it is also needed to evaluate the segmented electrodes used in other kinds of Hall thrusters, such as Aton [17,18] involved in this paper. This paper presents detailed numerical results that how the length of both low-emissive and non-emissive electrodes near the exit of a 1kw Aton-type Hall thruster affects the ionization position, electric potential distribution, ion acceleration process, and the ion beam angular distribution at the exit plane by a fully kinetic 2D Particle-in-Cell (PIC) model for gas flow rate ranged in 1 ∼ 3 mg/s.…”

Effect of Preionization on the Erosion of the Discharge Channel Wall in a Hall Thruster Using a Kinetic Simulation

“…3. The current, based on reference [33], is 300 A for the external magnetic coil, 450 A for the internal magnetic coil, and 35 A for the additional magnetic coil. Contours of the magnetic field are also presented in Fig.…”

Study on the influences of ionization region material arrangement on Hall thruster channel discharge characteristics

“…For Xe: β 0 =2.2×10 −14 m 3 s −1 , T * =4 eV. When the density of atomic number n z a ( ) is almost constant, equation (18) can be approximately expressed as: From equation (19), we can see that the ionization rate increases along with the growth of electron temperature or electron density in the discharge channel. Figure 8 shows the distribution of the ionization rate along the axial direction z before and after the segme-nted electrode placement.…”