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EX/4-2 · The "hybrid" scenario in JET: towards its validation for ITER
E. H. Joffrin1), A.C.C. Sips2), J.F. Artaud1), A. Becoulet1), R. Budny3), P. Buratti4), P. da Silva Aresta Belo5), C.D. Challis6), F. Crisanti4), M. de Baar7), P. de Vries6), C. Gormezano4), C. Giroud6), O. Gruber2), G.T.A. Huysmans1), F. Imbeaux1), A. Isayama8), X. Litaudon1), P.J. Lomas6), D.C. McDonald6), Y.S. Na9), S.D. Pinches2), A. Staebler2), T. Tala10), A. Tuccillo4), K.D. Zastrow6), JET-EFDA Contributors
1) Association EURATOM-CEA, Saint Paul lez Durance, France
2)Max-Planck-Institut fur Plasmaphysik, Euratom Association, 85748, Garching Germany.
3)Plasma Physics Laboratory, Pinceton University, Princeton USA.
4)Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Frascati , Italy.
5)Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
6)Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB, UK.
7)FOM-Rijnhuizen, Ass. Euratom-FOM, TEC, PO Box 1207, 3430 BE Nieuwegein, NL.
8)Japan Atomic Research Institute, Naka-machi, Naka-gun, Ibaraki-ken 311-0193, Japan
9)Korean Basic Science Institute, 52 Yeoeun-Dong, Yusung-Gu, Daejeon,305-333, Korea
10)Association EURATOM-TEKES, VTT Processes, P.O. Box 1608, FIN-02044 VTT, Finland.
Abstract: In 2003, the performance of the “hybrid” regime have been successfully validated in JET up to bN=2.8 at low toroidal field (1.7T), with plasma triangularity and normalised Larmor radius (r*) corresponding to identical ASDEX Upgrade discharges. Stationary conditions have been achieved with the figure of merit for fusion gain (H89.bN/q952) reaching 0.42 at q95=3.9. The JET discharges are showing similar MHD, edge and current profile behaviour than in ASDEX Upgrade. In addition, the JET experiments have extended the hybrid scenario operation at higher toroidal field 2.4T and lower r* towards projected ITER values. Using this database, transport and confinement properties are characterised with respect to the standard H-mode regime. Moreover, trace tritium have been injected to assess the diffusion and convective coefficients of the fusion fuel. The maximisation of confinement and stability properties provides to this scenario a good probability for achieving high fusion gain at reduced plasma current for duration up to 2000s in ITER.
Keywords: advanced tokamak, neoclassical tearing modes, scaling law, steady state conditions, trace tritium transport experiments,
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