Low-frequency electron dynamics in the near field of a Hall effect thruster

Journal Article · Thu Jun 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2209628· OSTI ID:20787399

Albarede, L; Mazouffre, S; Bouchoule, A; Dudeck, M ^[1]

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1. Laboratoire d'Aerothermique, 1C avenue de la Recherche Scientifique, 45071 Orleans (France)

Time-resolved electrostatic probe measurements were performed in the near field of a SPT100-ML Hall effect thruster in order to investigate electron properties changes on a microsecond time scale. Such measurements allow one to monitor the electron temperature T{sub e}, the electron density n{sub e}, as well as the plasma potential V{sub p} during a time period that corresponds to one cycle of a breathing-type plasma oscillation with f{approx_equal}15-30 kHz. Although T{sub e}(t) stays constant in time, n{sub e}(t) and V{sub p}(t) oscillate with the discharge current waveform frequency. The observed time delay between n{sub e} and anode discharge current (Id{sub a}) waveforms, which is of approximately 7 {mu}s, is linked to the ion transit time from the ionization layer to the probed near-field region. The same time gap is measured between V{sub p}(t) and Id{sub a}(t), however V{sub p}(t) and n{sub e}(t) are in phase opposition. The electron density reaches its highest value at the very moment ions are ejected out of the thruster discharge chamber, which also corresponds to the instant the cathode potential is the most negative. Such a behavior images the need for ion beam neutralization. Further, it is shown that there is a strong correlation between the electron dynamics and the presence of high frequency (HF) plasma oscillations in the megahertz range: HF fluctuations are the strongest when n{sub e} is the highest.

• OSTI ID: 20787399
• Journal Information: Physics of Plasmas, Vol. 13, Issue 6; Other Information: DOI: 10.1063/1.2209628; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CORRELATIONS
ELECTRIC CURRENTS
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRONS
ELECTROSTATIC PROBES
FLUCTUATIONS
HALL EFFECT
ION BEAMS
ION TEMPERATURE
IONS
KHZ RANGE
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA DENSITY
PLASMA GUNS
PLASMA POTENTIAL
PLASMA WAVES
RADIATION TRANSPORT
THRUSTERS
TIME DELAY
TIME RESOLUTION
WAVE FORMS