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Please use this identifier to cite or link to this item: http://hdl.handle.net/2014/41012

Title: Potential fluctuations and energetic ion production in hollow cathode discharges
Authors: Goebel, Dan M.
Jameson, Kristina K.
Katz, Ira
Mikellides, Ioannis G.
Keywords: keeper
probes
wares
Issue Date: 13-Oct-2007
Publisher: American Institute of Physics
Citation: Physics of Plasmas 14, 103508 2007 DOI: 10.1063/1.2784460
Abstract: Ions with energies significantly in excess of the applied discharge voltage have been reported for many years in hollow cathode discharges. Models of dc potential hills downstream of the cathode and instabilities in postulated double layers in the cathode orifice have been proposed to explain this, but have not been substantiated. Measurements of the dc and rf plasma density and potential profiles near the exit of hollow cathodes by miniature fast-scanning probes suggests that turbulent ion acoustic fluctuations and ionization instabilities in the cathode plume significantly increase the energy of the ions that flow from this region. Increases in the discharge current and/or decreases in the cathode gas flow enhance the amplitude of the fluctuations and increase the number and energy of the energetic ions, which increases the erosion rate of the cathode electrodes. The transition from the quiescent "spot mode" to the noisy "plume mode" characteristic of these discharges is found to be a gradual transition of increasing fluctuation amplitudes.
URI: http://hdl.handle.net/2014/41012
Appears in Collections:JPL TRS 1992+

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