Author/Authors :
McLean، نويسنده , , A.G. and Elder، نويسنده , , J.D. and Stangeby، نويسنده , , P.C. and Allen، نويسنده , , S.L. and Boedo، نويسنده , , J.A. and Brooks، نويسنده , , N.H. and Fenstermacher، نويسنده , , M.E. and Groth، نويسنده , , M. and Lisgo، نويسنده , , S. and Nagy، نويسنده , , A. and Rudakov، نويسنده , , D.L. and Wampler، نويسنده , , W.R. and Watkins، نويسنده , , J.G. and West، نويسنده , , W.P. and Whyte، نويسنده , , D.G.، نويسنده ,
Abstract :
As part of a study of carbon–tritium co-deposition, we carried out an experiment on DIII-D involving a toroidally symmetric injection of 13CH4 at the top of a LSN discharge. A Monte Carlo code, DIVIMP-HC, which includes molecular breakup of hydrocarbons, was used to model the region near the puff. The interpretive analysis indicates a parallel flow in the SOL of M∥ ∼ 0.4 directed toward the inner divertor. The CH4 is ionized in the periphery of the SOL and so the particle confinement time, τc, is not high, only ∼5 ms, and about 4X lower than if the CH4 were ionized at the separatrix. For such a wall injection location, however, approximately 60–75% of the CH4 gets ionized to C+, C2+, etc., and is efficiently transported along the SOL to the inner divertor, trapping hydrogen by co-deposition there.
Keywords :
Carbon impurities , DIII-D , DIVIMP , Edge modeling , Hydrocarbons
