IAEA Fusion Energy Conference 2010

Proceedings of the 23rd IAEA Fusion Energy Conference
Daejeon, 11-16 October 2010

Organized by the International Atomic Energy Agency
and hosted by the Government of the Republic of Korea


(ITR/P1-14) Experimental Investigation And Validation of Neutral Beam Current Drive for ITER through ITPA Joint Experiments

T. Suzuki1), R.J. Akers2), D.A. Gates3), S. Günter4), W.W. Heidbrink5), J. Hobirk4), T.C. Luce6), M. Murakami7), J.M. Park7), M. Turnyanskiy2), and the ITPA “Integrated Operations Scenarios” Topical Group members and experts
1) Japan Atomic Energy Agency, 801-1, Mukoyama, Naka, Ibaraki-ken 311-0193, Japan
2) CCFE/EURATOM Fusion Association, Culham Science Centre, Abingdon, UK
3) Princeton Plasma Physics Laboratory, Princeton, USA
4) Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching, Germany
5) University of California, Irvine, USA
6) General Atomics, San Diego, USA
7) Oak Ridge National Laboratory, Oak Ridge, USA

Abstract.  Joint experiments investigating the off-axis neutral beam current drive (NBCD) capability to be utilized for advanced operation scenario development in ITER was conducted in 4 tokamaks (ASDEX Upgrade (AUG), DIII-D, JT-60U, and MAST) through the international tokamak physics activity (ITPA). The following results were obtained in the joint experiments, where the toroidal field, Bt, covered 0.3 - 3.7 T, the plasma current, Ip, 0.6 - 1.2 MA, and the beam energy, Eb, 67 - 350 keV. A current profile broadened by off-axis NBCD was observed in MAST. In DIII-D and JT-60U, NB driven current profile has been evaluated using motional Stark effect diagnostics and good agreement between the measured and calculated NB driven current profile was observed. In AUG (at low triangularity 0.2) and DIII-D, introduction of a fast ion diffusion coefficient of Db∼0.3 - 0.5 m2/s in the calculation gave better agreement at high heating power (5 and 7.2 MW, respectively), suggesting anomalous transport of fast ions by turbulence. It was found through these ITPA joint experiments that NBCD related physics quantities reasonably agree with calculations (with Db = 0 - 0.5 m2/s) in all devices when there is no MHD activity except ELMs.

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