1. Yves Martin Centre de Recherches en Physique des Plasmas Association Euratom - Confédération Suisse Ecole Polytechnique Fédérale de Lausanne (EPFL) CH - 1015 Lausanne, Switzerland ITPA – CDBM H-mode threshold database Threshold database discussion April 2006 - Princeton

2. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 2 Programme Server location Recommended scaling New data Interest ? NSTX, MAST, JFT-2M, CHS New analysis Variation of n e and B t dependence with tokamak size Effect of hysteresis Aspect ratio dependence of threshold power P L /P Thresh for different ELM types / H-mode regimes Dimensionally correct scaling Conferences / Papers Future Action list Long term

3. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 3 Server location Database is now on a server in Garching, behind a ‘heavy’ firewall Some work has been devoted to the installation of a MySQL database server in Lausanne Database management would be easier on a local server Discussion yesterday => Threshold DB remains in Garching

4. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 4 Recommended scaling It was decided to keep 2 scalings: Full dataset Reduced ITER like dataset ITER: Pth(n=0.5) = 31 [28-33] MW Pth(n=1.0) = 42 [38-47] MW

5. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 5 Reduced dataset ITER-like dataset ITER: Pth(n=0.5) = 55 [49-61] MW Pth(n=1.0) = 92 [79-107] MW

6. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 6 Recommended scaling Next steps: Release the database with the selection parametersYM Confirm data selection (individually /tokamaks)ALL Insert correctionsYM Estimate fit parametersALL

7. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 7 New data It was planned to add some new data in the database Is there any interest ? Who would like to contribute ? NSTX? MAST? JFT-2M? CHS ? Others?

8. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 8 New analysis – n e and B t individual dependences Threshold power has a strong dependence in plasma density (1) P thresh ~ ne 0.47 ; (3) P thresh ~ ne 0.74 => H-mode should be initiated at low density Threshold power dependence on density for individual devices Alcator C-mod ASDEX Upgrade DIII-DJETJT-60U R [m]0.671.621.682.883.26 n e exponent0.40.420.690.820.87

9. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 9 New analysis – Effect of hysteresis H-mode phaseHL transition Selection: ALL entries with PHASE indicating H-mode or HL transition => No clear link between scaling and P L /P Thresh. Overall statistics only. Should look for individual discharges …

10. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 10 New analysis – Threshold for different ELM types Previous figure already indicates operational domains for different ELM types Collaborate with other groups to determine the required power to access different H-mode regimes (esp. Hybrid H-mode)

11. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 11 Conferences / papers Conference APS ? EPS 2007 H-mode WS 2007 Paper NF paper  Data description  Basic scalings  Dimensionless scaling  Influence of aspect ratio (new data & new parameters)  Influence of data selection on scalings  Influence of scaling parameters  Errors in variables  Recommended scalings

12. Yves Martin, ITPA TG CDBM LH Transitions, April 2006, Princeton 12 Future Future of the database ? Threshold power prediction for ITER construction  Done and used  Would it change ? H-mode access in ITER discharge planning / control  Role of ITPA ?  Threshold power / definition of the ‘route’ Prediction for future devices  Exercise done for DEMO  Wait for ITER data ?  Which improvement ? Improvement of LH transition understanding  Extraction of information to be used by modellers  Role of 0D databases / 1D (profile) database