(EX/P1-12) Prospects for Steady-State Scenarios on JET

X. Litaudon1), J.P.S. Bizarro2), C.D. Challis3), F. Crisanti4), P.C. De Vries3), P. Lomas3), F.G. Rimini1), T.J.J. Tala5), R. Akers3), Y. Andrew3), G. Arnoux1), J.F. Artaud1), Yu. F. Baranov3), M. Beurskens3), M. Brix3), R. Cesario4), E. De La Luna6), W. Fundamenski3), C. Giroud3), N.C. Hawkes3), A. Huber7), E. Joffrin3), R.A. Pitts8), E. Rachlew9), S.D.A. Reyes-Cortes2), S. Sharapov3), O. Zimmermann7)
1) Association Euratom-CEA, CEA/DSM/DRFC-Cadarache 13108, St Paul Durance, France
2) Centro de Fusão Nuclear, Associação Euratom-IST, Instituto Superior Técnico, 1049-001 Lisboa, Portugal
3) Association Euratom-UKAEA, Culham Science Centre OX14 3DB Abingdon, OXON UK
4) Associazione Euratom-ENEA, ENEA Centro Ricerche Frascati C.P. 65, 00044 Italy
5) Association Euratom-TEKES, VTT, P.O. Box 1000, FIN-02044 VTT, Finland
6) Asociacion Euratom-CIEMAT, ES Avenida Complutense 22 E-28040 Madrid Spain
7) Assoziationen Euratom-Forschungszentrum, Jülich D- 52425 Jülich Germany
8) Association Euratom-Confédération Suisse CRPP EPFL 1015 Lausanne Switzerland
9) Association Euratom-VR, Dept Phys., KTH, SE 10691, Stockholm Sweden

Abstract.  In addition to the development of the inductive ELMy-H mode, much effort and progress have been made to achieve plasma regimes more suitable for steady state tokamak operations, i.e. where a large fraction of the plasma current is non-inductively driven. These challenging scenarios (high beta operation) could lead to more efficient electricity production in a reactor without the need for large plasma current. It will be argued in the paper based on recent modelling benchmarked on experimental results that the power upgrade on JET will allow the development of high fusion performance non-inductive scenarios that could be made in conditions as close as possible to those required for ITER. The tools of the long term JET programme in preparation of ITER operation is the new ITER-like ICRH antenna (15 MW), an upgrade of the NB power (35MW/20s or 17.5MW/40s), a new ITER-like first wall, a new pellet injector for ELM control together with improved diagnostic and control capability. Operation with the new wall will set new constraints on non-inductive scenarios that already needed to be addressed. In this context, to estimate the fusion performances and the non-dimensional parameters that could be reached at high density and power, a simplified 0-D model has been developed based on global scaling for the energy confinement time and the current drive efficiencies. This model has been benchmarked on the existing JET database where the prediction are compared to the experimental results obtained in full current drive regimes. A power level of 45MW gives access to JET regime where, as in a future steady state reactor, the bootstrap current is maximised together with the fusion yield and not at its expense. This approach that allows to scan the operating space has been complemented with more sophisticated 1-D modelling of the full time dependent scenario with the complete suite of heating and current drive models. Finally, it will report on the 2006 experimental results where with the available heating and current drive power levels these long term scientific issues are addressed but in a separate manner in view of preparing the full scenario integration when the JET power upgrades will be completed.

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