Analysis of chamber simulations of long collecting probes in high-speed dense plasmas

Brian E. Gilchrist, Sven G. Bilén, Éric Choinière, Alec D. Gallimore, Timothy B. Smith

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Chamber tests of simulated electrodynamic tethers (EDTs) of different geometries operating in a dense high-speed plasma are described. The geometries tested and described here are cylindrical and flat-ribbon tape. By moving the probe samples relative to the plasma source it was possible to vary the density and therefore the effective width over a range of approximately 1 to 2 Debye lengths (λD) for the cylinder sample and 6 to 19 λD for the tape samples. Several important conclusions can be drawn from the tests. 1) The current-voltage characteristics of the cylinder behave as predicted by orbital-motion-limited (OML) current collection theory in the saturation region. 2) The tape tether had comparable current levels to a theoretical equal area OML cylinder up to an effective width of at least ∼11λD and possibly wider. 3) Orienting the tape samples parallel or perpendicular to the plasma flow yielded different current responses (perpendicular is larger) above a bias potential that is near the estimated energy of the incoming beam ions. The observed difference was generally more pronounced at larger effective widths (higher densities). 4) It was also necessary to be above this bias potential to have a V0.5 current-voltage character appropriate for an ideal cylinder in the OML regime. It is concluded that wide ribbon-like tape tethers can be effective current collectors but that velocity effects will be a factor to consider, especially as relative width of the tape tether (with respect to λD) grows.

Original languageEnglish (US)
Pages (from-to)2023-2034
Number of pages12
JournalIEEE Transactions on Plasma Science
Volume30
Issue number5 II
DOIs
StatePublished - Oct 2002

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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