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12th ITPA CDBM & TP WS H-mode threshold database - Summary May 2007 - Lausanne. Yves Martin Centre de Recherches en Physique des Plasmas Association Euratom - Confédération Suisse Ecole Polytechnique Fédérale de Lausanne (EPFL) CH - 1015 Lausanne, Switzerland. Threshold database status.
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12th ITPA CDBM & TP WSH-mode threshold database - SummaryMay 2007 - Lausanne Yves Martin Centre de Recherches en Physique des Plasmas Association Euratom - Confédération Suisse Ecole Polytechnique Fédérale de Lausanne (EPFL) CH - 1015 Lausanne, Switzerland
Threshold database status • Work on the DB • Changes in DB • AUG: data selection: 12 T.S. removed; 10 T.S. added • CMOD: density corrected in one discharge • New version released IGDBTH4v6b • 4v7 for promised new data • Recommended scaling • Almost ready to be released (will be released at IAEA TM H-mode) • Promised JFT-2M data (6 t.s.) will be incorporated • CMOD data selection check under way
Presentations • Recent LH Threshold Results on Alcator C-mod, J.Snipes • LH transition happens at same value of rotation for LSN, DN, USN. Role of SOL flows. • LH Transition in DIII-D and ITER Issue Implications, J.DeBoo for G.Wang • Work on current issues • Relation between confinement and distance to LH power threshold in ASDEX Upgrade, F.Ryter • Work on current issues • Overview of 2006 – 2007 L-H transition studies on JET, Y.Andrew • Effect of X-point location on threshold power dependence on plasma edge density
Critical issues • Density dependence of threshold power • Pthresh ~ nean • Density exponent increases with machine size • Statistical errors in such analysis • Increases with magnetic field (?) • Depends on X-point geometry • Density at minimum threshold power • Increase in the threshold power at low density • Depends on magnetic field ? (high density >.5 1020in CMOD) • Dependence on other parameters (impurities, DIII-D: locked modes/error field coils) • Power ratio (PL/Pthresh) in good confinement regimes • Good confinement obtained with power ratio between 1.2 and 4 • HH factor ~1 with 1< PL/Pthresh<1.5 in AUG
Publications • Paper at IAEA TM H-mode (YM, Sep 2007, Japan) • Recommended scaling • Density dependence of threshold power • Density at minimum threshold power • Power ratio (PL/Pthresh) in good confinement regimes • Power ratio in ITER
Action list I • New data • JFT-2M, CHS (TT, done during this meeting!) • NSTX (SK, before next meeting) • MAST (MV, tbd) • Data check • CMOD (JS, 30 June) • Description of data selection criteria (YM, 31 May + next meeting) • New version of DB • data checked IGDBTH4v6c (asap, CMOD) • New data: IGDBTH4v7 (before next meeting) • Recommended scaling • Estimation with changes in data selection (asap, data checked) • Errors, Kadomtsev constraint (before next meeting)
Action list II • Density dependence of threshold power • Identify dedicated density scans in threshold DB (CMOD, done during meeting, others: 31 May) • Verify if experiments were done and not in threshold DB, then provide data (All, 30 June) • Density at minimum threshold power • Joint experiment proposed (CDB-10) • Power ratio (PL/Pthresh) in good confinement regimes • Identify published good confinement results which are not included in the confinement DB (All, 30 June) and provide data • Extract evolution of power ratio for a few typical discharges (All, 15 August) • Search for evolution of power ratio in ITER scenarios (YM, 30 June)
Action list III • Isotopic effect, Hydrogen identity experiments • Look for existing data in DB (YA, next meeting) • Perform experiment, at least check if possible (FR, next meeting) • IAEA TM paper • Circulate draft of abstract (YM, 25 May) • Send abstract (YM, 31 May) • Paper (YM, before ws!)