1. A review of the recent expanded boundary divertor experiments in the doublet III device
- Author
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N.H. Brooks, Stav Rd, C. Armentrout, A. J. Lieber, T. Todd, G.L. Jahns, J.L. Luxon, J.S. deGrassie, K. H. Burrell, J. Lohr, M.A. Mahdavi, S.K. Wong, J.R. Smith, S.S. Wojtowicz, D. Vaslow, R. Chase, A.C. Riviere, R.K. Fisher, R. T. Snider, S. Ejima, B.B. Brown, F.B. Marcus, R. J. Groebner, R. Callis, J.C. DeBoo, C. L. Hsieh, J.C. Wesley, R. L. Freeman, T.W. Petrie, R.D. Stambaugh, F. Blau, E.S. Fairbanks, T. S. Taylor, P.I. Petersen, D. R. Eames, Nobuyoshi Ohyabu, R. P. Seraydarian, G. Bramson, and C.H. Muller
- Subjects
Nuclear and High Energy Physics ,Argon ,Chemistry ,Divertor ,chemistry.chemical_element ,Plasma ,Nuclear Energy and Engineering ,Physics::Plasma Physics ,Phase (matter) ,Radiative transfer ,General Materials Science ,Atomic physics ,Order of magnitude ,Beam (structure) ,Line (formation) - Abstract
Analysis of the expanded boundary divertor in Doublet III reveals a medium density operating regime ( n e ≲ 4 × 10 13 cm -3 ), in which (1) the divertor density ne(Div) rises with the cube of the main plasma line average density, n e , and (2) the neutral pressure at the exhaust end of the divertor has a quadratic dependence on n e (with divertor plasma temperatures ≲ 15 eV). In this regime, injection of argon into the discharge results in a steady state concentration of argon, which is two orders of magnitude higher in the divertor plasma than in the main discharge. This trapping effect suggests that the argon concentration in the divertor region may be useful as an externally controllable parameter; that is, injected argon effectively cools the plasma boundary, yet is not deleterious to the plasma as a whole. A model which successfully describes the behavior of the edge and divertor plasmas in ohmically heated discharges suggests that these desirable trapping and radiative features may be maintained in the high powered neutral beam heating phase.
- Published
- 1982
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