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Abstract

The comprehensive CQL3D Fokker-Planck/Quasilinear simulation code has been benchmarked against experiment over a wide range of electron cyclotron conditions in the DIII�D tokamak (C.C. Petty et al., 14th Topical Conf. on RF Power in Plasmas, 2002). The same code, in disagreement with experiment, gives 560 kA of ECCD for a well documented, completely ECCD-driven, 100 kA TCV shot [O. Sauter et al, PRL, 2000]. Recent work (R.W. Harvey et al, Phys. Rev. Lett., 2002) has resolved the differences as due to radial transport at a level closely consistent with ITER scaling. Transport does not substantially affect DIII�D ECCD, but at similar ECH power has an overwhelming effect on the much smaller TCV. The transport is consistent with electrostatic-type diffusion (D?? constant in velocityspace) and not with a magnetic-type diffusion (D?? 8 |v|||).

Fokker-Planck simulation of Ohmic reversed field pinch (RFP) discharges in the MST device reveals transport velocity dependence stronger than |v||| will give agreement with current and soft X-ray spectra in standard discharges, but in the higher confinement, current profile controlled PPCD discharges, transport is again electrostatic-like. This is consistent with the object of PPCD, which is to replace magnetic turbulence driven current with auxiliary CD to improve transport. The tokamak and high-confinement RFP results mutually reinforce the constant-in-velocity-space "electrostatic-type turbulence" conclusion. The steady-state energy and toroidal current are governed by the same radial transport equation.

Additional information

Authors: HARVEY R W, CompX, Del Mar (US);SAUTER O, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM-Confédération Suisse (CH);NIKKOLA P, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM-Confédération Suisse (CH);PRATER R, General Atomics, San Diego (US);O'CONNELL R, University of Wisconsin, Madison (US);FOREST C B, University of Wisconsin, Madison (US)
Bibliographic Reference: An oral report given at: 12th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating Organised by: Association Euratom-CEA, Cadarache Held at: Aix-en-Provence (FR) May 13-16, 2002
Availability: Workshop papers are available online at: http://wshop.free.fr/ec12/ This paper is also published in report LRP 726/02, available free of charge from: École Polytechnique Fédérale de Lausanne, Ecublens, CH-1015 Lausanne Fax +41-21-69347
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