Figure 1
Figure 2
High Frequency Oscillations in Hall Thrusters
High-frequency oscillations (1-100 MHz) in Hall thrusters have apparently eluded significant experimental scrutiny. A diagnostic setup, consisting of single-tip Langmuir probe, special shielded probe connector-positioner (Figure 1), and electronic impedance-matching circuit was successfully built and calibrated. Through simultaneous high-frequency probing of the Hall thruster plasma at multiple locations, high-frequency waves have been identified and characterized. For various thruster operating conditions the detected waves are determined to propagate in the azimtuhal direction inside the thruster channel. The presence of several modes with multiple frequencies (Figure 2) as well as the relation of the wave phase velocity to the electron azimuthal drift velocity suggests that the detected modes manifest the Rayleigh-type instability, which has been predicted in our theoretical study.
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Figure 1 |
Figure 2 |
For more details, see our publications.
Copyright © 2003 Princeton Plasma Physics Laboratory