The potential and ion velocity distribution in Hall thrusters
- Paper number
IAC-09.C4.8.6
- Author
Mr. Yongjun Choi, United States
- Year
2009
- Abstract
Hall effect thrusters represent an efficient form of electric propulsion devices in which ions are accelerated by an electric field and used as major propellant. Hall thrusters are able to perform better than chemical propulsion systems because Hall thrusters can create higher specific impulse and do not need to carry any oxidizer, so allow a larger payload. Experimental investigation of the magnetic fields distribution within Hall thrusters shows that the radial component is dominant. However, it was found in experiments that under certain operating conditions a distinctive jet-like potential structure developed in the Hall thruster channel. In other words, the potential distribution deviates from the magnetic field profile and the peak of the electric field is shifted downstream of the exit plane. This structure may result in a significant divergence of beam ions as they are accelerated out of the thruster. Therefore, prediction of the potential and ion velocity distribution is very important in develop electric propulsion devices. In this study, a kinetic model of the plasma in a Hall thruster channel is developed which takes into account the magnetic field. The model is an attempt to explain the experimentally found non-uniform potential distribution and predict the ion velocity across the thruster channel. Two dimensional particle simulation of an SPT type Hall thruster channel plasma is investigated using VORPAL, a PIC-DSMC code developed at Tech-X. For thruster channel plasma simulation, the direct simulation Monte Carlo (DSMC) methods simulates the collisions of particles (electron, ions and atoms) and the Particle-In-Cell (PIC) technique models the transport of ions and electrons in electric fields. All particles are treated kinetically.
- Abstract document
- Manuscript document
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