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Title: Electric field divertor plasma pump

An electric field plasma pump includes a toroidal ring bias electrode (56) positioned near the divertor strike point of a poloidal divertor of a tokamak (20), or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix (40) of the poloidal divertor contacts the ring electrode (56), which then also acts as a divertor plate. A plenum (54) or other duct near the electrode (56) includes an entrance aperture open to receive electrically-driven plasma. The electrode (56) is insulated laterally with insulators (63,64), one of which (64) is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode (56) and a vacuum vessel wall (22), with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E.times.B/B.sup.2 drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable.
Inventors:
 [1]
  1. (San Diego, CA)
Issue Date:
OSTI Identifier:
869531
Assignee:
United States of America as represented by United States (Washington, DC) LLNL
Patent Number(s):
US 5353314
Contract Number:
AC03-89ER51114; AC05-84OR21400; W-7405-ENG-48; AC04-76DP00789
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
electric; field; divertor; plasma; pump; toroidal; bias; electrode; 56; positioned; near; strike; poloidal; tokamak; 20; similar; plasma-confining; apparatus; optimum; pumping; separatrix; 40; contacts; plate; plenum; 54; duct; entrance; aperture; receive; electrically-driven; insulated; laterally; insulators; 63; 64; opposite; established; vacuum; vessel; wall; 22; polarity; applied; relative; selected; resultant; interacts; magnetic; existing; create; times; drift; velocity; drives; pumped; flow; insensitive; variations; intentional; otherwise; geometry; pressure; buildups; connected; excess; 10; mtorr; achievable; bias applied; poloidal divertor; vessel wall; vacuum vessel; electric field; magnetic field; positioned near; positioned opposite; drift velocity; receive electrical; duct connected; pressure buildup; plasma pump; /376/