(IT/P1-21) Disruption Characterization and Database Activities for ITER

J.C. Wesley1), A.W. Hyatt1), E.J. Strait1), D.P. Schissel1), S.M. Flanagan1), T.C. Hender2), Y. Gribov3), P.C. deVries2), E.J. Fredrickson4), D.A. Gates4), R.S. Granetz5), M. Johnson2), Y. Kawano6), J. Lister7), R. Martin2), J. Menard4), G. Pautasso8), M. Sugihara3)
1) General Atomics, San Diego, California, United States of America
2) Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, United Kingdom
3) ITER International Team, Naka, Ibaraki, Japan
4) Princeton Plasma Physics Laboratory, Princeton, New Jersey, United States of America
5) Plasma Science Fusion Center, Massachusetts Institute of Technology, Cambridge Massachusetts, United States of America
6) Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki, Japan
7) Association Euratom-Confederation Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Laussane, Lausanne, Switzerland
8) Max Planck Institut für Plasmaphysik, Garching, Garching bei München, Germany

Abstract.  Disruption characterization and database development and analysis activities conducted for ITER under the aegis of the International Tokamak Physics Activity (ITPA) Topical Group on MHD, Control and Disruption are described. Accomplishments during 2005-2006 include: 1) formation of an International Disruption Database (IDDB) Working Group, 2) implementation of an MDS plus-based IDDB infrastructure for collection and retrieval of disruption-relevant tokamak data, and 3) collection of a ``version-1” data set from seven elongated-plasma-cross-section tokamaks. Database content available as of March 2006 comprises some 3500 disruptions from four tokamaks: Alcator C-Mod, DIII-D, JET and NSTX. Analysis of the current quench data from this provisional data set has allowed the IDDB Working Group to provide an updated recommendation, tCQ/S = 1.67 ms/m2, for the lower bound on the expected plasma current decay time in ITER. Here tCQ is the linear-basis current decay time and S is the before-disruption plasma cross-section area. This recommendation, derived from C-Mod, DIII-D, and JET data, applies for plasmas with aspect ratio A in the range 2.5≤A≤3.5. Consideration of the low-A (NSTX) data presently in the IDDB shows that a further modification of this formula is required to accurately predict the lower bound on tCQ/S for low-A plasmas. Incorporation of additional low-A data and definitive development of low-A guideline is in progress. Plans for further current quench data analysis and for future expansion of the scope and content of the IDDB to include halo current, thermal energy, runaway electron and 2-D and 3-D plasma equilibrium evolution data have been identified.
* Work supported in part by the U.S. Department of Energy under DE-FC02-04ER54698 and DE-AC02-76CH03073. Encouragement of the ITER International Team, especially fromM. Shimada, and support of the ITPA Coordinating Committee is gratefully acknowledged.

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