Long wavelength gradient drift instability in Hall plasma devices. II. Applications

Journal Article · Wed May 15 04:00:00 UTC 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4804281· OSTI ID:22218595

Frias, Winston; Smolyakov, Andrei I. ^[1]; Kaganovich, Igor D.; Raitses, Yevgeny ^[2]

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1. Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon SK S7N 5E2 (Canada)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Hall plasma devices with electron E × B drift are subject to a class of long wavelength instabilities driven by the electron current, gradients of plasma density, temperature, and magnetic field. In the first companion paper [Frias et al., Phys. Plasmas 19, 072112 (2012)], the theory of these modes was revisited. In this paper, we apply analytical theory to show that modern Hall thrusters exhibit azimuthal and axial oscillations in the frequency spectrum from tens KHz to few MHz, often observed in experiments. The azimuthal phase velocity of these modes is typically one order of magnitude lower than the E × B drift velocity. The growth rate of these modes scales inversely with the square root of the ion mass, ∼1/√(m){sub i}. It is shown that several different thruster configurations share the same common feature: the gradient drift instabilities are localized in two separate regions, near the anode and in the plume region, and absent in the acceleration region. Our analytical results show complex interaction of plasma and magnetic field gradients and the E × B drift flow as the sources of the instability. The special role of plasma density gradient is revealed and it is shown that the previous theory is not applicable in the region where the ion flux density is not uniform. This is particularly important for near anode region due to ionization and in the plume region due to diverging ion flux.

• OSTI ID: 22218595
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 20; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANODES
DRIFT INSTABILITY
ELECTRIC CURRENTS
ELECTRON TEMPERATURE
ELECTRONS
FLUX DENSITY
ION TEMPERATURE
IONIZATION
IONS
KHZ RANGE
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MHZ RANGE
OSCILLATIONS
PHASE VELOCITY
PLASMA DENSITY
PLASMA WAVES
THRUSTERS
WAVELENGTHS