Growth of the lower hybrid drift instability in the plume of a magnetically shielded Hall thruster
- 17 May 2021
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 129 (19), 193301
- https://doi.org/10.1063/5.0048706
Abstract
Analytical and numerical investigations have been carried out that show the lower hybrid drift instability is active in a region of low-β plasma outside the discharge channel of a magnetically shielded Hall thruster. The region is located downstream of the inner front pole magnet and is contained by the thruster ion beam and hollow cathode plume. It is found that large enough E × B and diamagnetic drifts in the out-of-plane (azimuthal) direction are produced in this region to destabilize lower hybrid waves, even in the presence of electron collisions. The results have been obtained by solving an electrostatic dispersion relation in which the density inhomogeneity is accounted for in the velocity distribution function of the strongly magnetized electrons. Ions in the azimuthal direction have been treated as stationary and unmagnetized. The plasma properties in the dispersion have been provided independently by large-scale 2D multi-fluid/particle-in-cell simulations. The growth rates are found to be even greater than those associated with the modified two-stream instability, which was also predicted recently to be active in this region. The implication of the findings is that ions may be heated anomalously by these instabilities, in both the out-of-plane and in-plane directions perpendicular to the applied magnetic field, thereby altering the velocity field and enhancing the energy of those ions that strike nearby thruster surfaces.Keywords
Funding Information
- Jet Propulsion Laboratory
This publication has 50 references indexed in Scilit:
- Hall thruster plasma fluctuations identified as the E×B electron drift instability: Modeling and fitting on experimental dataPhysics of Plasmas, 2013
- Evidence of nonclassical plasma transport in hollow cathodes for electric propulsionJournal of Applied Physics, 2007
- Lower‐hybrid‐drift and modified‐two‐stream instabilities in current sheet equilibriumJournal of Geophysical Research, 2004
- Cross-Field-Current Driven Lower-Hybrid Instability and Stochastic Ion HeatingPhysical Review Letters, 1977
- Measurements of Plasma Density Distribution and Current-Sheath in the Implosion Phase of a Theta-Pinch DischargePhysical Review Letters, 1974
- Turbulence Spectrum Observed in a Collision-Free-Pinch Plasma by CLaser ScatteringPhysical Review Letters, 1974
- Low-Frequency Instabilities in Magnetic PulsesPhysical Review A, 1971
- High—Mach-Number Turbulent Magnetosonic ShocksPhysical Review Letters, 1971
- Observation of collisionless plasma heating by strong shock wavesThe European Physical Journal A, 1969
- Measurement of Light scattered from Density Fluctuations within a Collisionless ShockNature, 1969