Flowing plasmas are of significant interest due to their role in astrophysical phenomena and potential applications in magnetic-confined fusion and spacecraft propulsion. The acceleration of a charge-neutral plasma beam using the radio-frequency self-bias concept could be particularly useful for the development of neutralizer-free propulsion sources. However, the mechanisms that lead to space-charge compensation of the exhaust beam are unclear. Here, we spatially and temporally resolve the propagation of electrons in an accelerated plasma beam that is generated using the self-bias concept with phase-resolved optical emission spectroscopy. When combined with measurements of the extraction-grid voltage, ion and electron currents, and plasma potential, the pulsed-periodic propagation of electrons during the interval of sheath collapse at the grids is found to enable the compensation of space charge.
Transient propagation dynamics of flowing plasmas accelerated by radio-frequency electric fields
James Dedrick, Andrew Robert Gibson, Dmytro Rafalskyi, Ane Aanesland; Transient propagation dynamics of flowing plasmas accelerated by radio-frequency electric fields. Phys. Plasmas 1 May 2017; 24 (5): 050703. https://doi.org/10.1063/1.4983059
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