Perturbative studies of toroidal momentum transport using neutral beam injection modulation in the Joint European Torus: Experimental results, analysis methodology, and first principles modeling

Journal Article · Wed Sep 15 00:00:00 EDT 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3480640· OSTI ID:21432279

Mantica, P ^[1]; Tala, T ^[2]; Ferreira, J S ^[3]; Peeters, A G ^[4]; Salmi, A ^[5]; Strintzi, D ^[6]; Weiland, J ^[7]; Brix, M; Giroud, C; Corrigan, G; Zastrow, K -D ^[8]; Naulin, V ^[9]; Tardini, G ^[10]

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1. Istituto di Fisica del Plasma, EURATOM/ENEA-CNR Association, 20125 Milano (Italy)
2. VTT, Association EURATOM-Tekes, P.O. Box 1000, FIN-02044 VTT (Finland)
3. Centro de Fusao Nuclear, Associacao EURATOM/IST, 1049-001 Lisbon (Portugal)
4. Centre for Fusion Space and Astrophysics, University of Warwick, Coventry 7AL (United Kingdom)
5. Association EURATOM-Tekes, Helsinki University of Technology, P.O. Box 2200, FIN-02150 TKK (Finland)
6. Association Euratom-Hellenic Republic, National Technical University of Athens, GR-15773 Athens (Greece)
7. Euratom-VR Association and Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)
8. Euratom/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
9. Association Euratom-Risoe, DTU, DK-4000 Roskilde (Denmark)
10. Max-Planck-Institut fuer Plasmaphysik, EURATOM/MPI Association, D-85748 Garching (Germany)

Perturbative experiments have been carried out in the Joint European Torus [Fusion Sci. Technol. 53(4) (2008)] in order to identify the diffusive and convective components of toroidal momentum transport. The torque source was modulated either by modulating tangential neutral beam power or by modulating in antiphase tangential and normal beams to produce a torque perturbation in the absence of a power perturbation. The resulting periodic perturbation in the toroidal rotation velocity was modeled using time-dependent transport simulations in order to extract empirical profiles of momentum diffusivity and pinch. Details of the experimental technique, data analysis, and modeling are provided. The momentum diffusivity in the core region (0.2<{rho}<0.8) was found to be close to the ion heat diffusivity ({chi}{sub {phi}/{chi}i{approx}}0.7-1.7) and a significant inward momentum convection term, up to 20 m/s, was found, leading to an effective momentum diffusivity significantly lower than the ion heat diffusivity ({chi}{sub {phi}}{sup eff}/{chi}{sub i}{sup eff{approx}}0.4). These results have significant implications on the prediction of toroidal rotation velocities in future tokamaks and are qualitatively consistent with recent developments in momentum transport theory. Detailed quantitative comparisons with the theoretical predictions of the linear gyrokinetic code GKW [A. G. Peeters et al., Comput. Phys. Commun. 180, 2650 (2009)] and of the quasilinear fluid Weiland model [J. Weiland, Collective Modes in Inhomogeneous Plasmas (IOP, Bristol, 2000)] are presented for two analyzed discharges.

• OSTI ID: 21432279
• Journal Information: Physics of Plasmas, Vol. 17, Issue 9; Other Information: DOI: 10.1063/1.3480640; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION HEATING
DISTURBANCES
JET TOKAMAK
NEUTRAL ATOM BEAM INJECTION
PLASMA SIMULATION
ROTATION
VELOCITY
BEAM INJECTION
CLOSED PLASMA DEVICES
HEATING
MOTION
PLASMA HEATING
SIMULATION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES