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(ITERP/04) Next Step Tokamak Physics: Confinement-oriented Global Database Analysis

O. J. Kardaun1), A. Kallenbach1), P. McCarthy1)2), F. Ryter1), A. Stäbler1), J. Stober1), W. Suttrop1), M. Valovic3), S. J. Fielding3), G. Bracco4), J. Cordey5), D. C. McDonald5), D. Hogeweij6), A. Sykes3), A. Dnestrovskij3)7), M. Valovic3), M. Walsh3), Y. R. Martin8), J. Ongena9), G. T. Hoang10), T. Aniel10), K. Thomsen5)11), S. V. Lebedev12), V. A. Kornev12), Yu. V. Esipchuk7), V. M. Leonov7), V. Vershkov7), M. J. Greenwald13), A. Hubbard13), J. C. DeBoo14), A. Cote15), G. Pacher15), C. Bush 16)17), S. Kaye17), T. Takizuka18), T. Fukuda18), Y. Kamada18), K. Tsuchiya18), Y. Miura19), N. Isei19), K. Tsuzuki19), A. Chudnovskij20)7), V. Mukhovatov20)7)
1) MPI für Plasmaphysik, Garching, Germany
2) University College Cork, Cork, Ireland
3) UKAEA, Culham, United Kingdom
4) ENEA, Frascati, Italy
5) JET Joint Undertaking, Abingdon, United Kingdom
6) FOM Instituut voor Plasmafysica, Jutphaas, The Netherlands
7) Kurchatov Institute, Moscow, Russia
8) CRPP, Lausanne, Switzerland
9) IPP Forschungszentrum, Juelich, Germany
10) CEA, Cadarache, France
11) EFDA Close Support Unit, Garching, Germany
12) Ioffe Institute, St. Petersburg, Russia
13) MIT, Cambridge, USA
14) General Atomics, San Diego, USA
15) CCFM Hydro-Quebec, Varennes, Canada
16) ORNL, Oak Ridge, USA
17) PPPL, Princeton, USA
18) JAERI, Naka Fusion Research Establishment, Naka, Japan
19) JAERI, Tokai Research Establishment, Naka, Japan
20) ITER Joint Central Team, Naka site, Japan

Abstract.  We describe and analyse an international multi-tokamak confinement database, both motivated by physics and with a view toward prediction of next-step burning-plasma experiments such as ITER. Significant additional ohmic and L-mode data have been assembled from several tokamaks, which has resulted in the `ITERL.DB2' dataset. Simple density-roll-over scalings are presented for ohmic confinement. For H-mode, the confinement time in the essentially enlarged data set ITERH.DB3 is compared with the ITERH-98P(y,2) reference scaling. A distinction is made between discharges with and without heavy gaspuff. Beyond a standard power-law scaling, the empirical `influence' on confinement of q95/qcyl, directly related to triangularity, and of the global density peaking factor (for L- and H-mode) is quantified. A log-linear quadratic formula is given which describes physically more precisely than ITERH-98P(y,2) the relation between the isotope effect and the heating power degradation of confinement, while predicting a similar thermal confinement time for ITER ( $ \tau_{E,th}^{}$ $ \simeq$ 3.5s). Based on a recently provided plasma edge dataset, `E.1', separate scalings of the plasma core and pedestal energy are derived. Finally, a class of nonlinear scalings is discussed which are suitable, in contrast to offset (non-)linear models, to fit roll-over dependence, and, simultaneously, the scaling of L-mode and H-mode confinement.

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IAEA 2001