Disruption, Halo Current and Rapid Shutdown Database Activities for ITER

Full text: 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 Stability are described. An ITPA International Disruption Database (IDDB) Working Group and a MDSplus-based IDDB infrastructure for collection and retrieval of disruption-relevant tokamak data, first established in 2006, comprises one of the several 'joint experiments' being conducted by the MHD Topical Group. Analysis reported in 2006 of the current quench data from 7 elongated-plasma tokamaks provided a new recommendation about the lower bound on the plasma current decay time expected in ITER. In 2010, expansion of the scope and content of the IDDB to encompass halo current data has been initiated, and new combined current decay and halo current data sets (shot records) from the seven previously-contributing tokamaks are expected. The analysis to be reported in this paper will provide an 'integrated' current decay and halo current basis for updated recommendations to the ITER Organization in regard to ITER halo current magnitude and toroidal asymmetry and how these attributes correlate with the parent plasma aspect ratio, elongation and triangularity and current and toroidal field magnitudes. The feasibility of interpreting database composite and device-specific data in terms of a 'statistical' load severity spectrum will be explored. Activity has been initiated to add IDDB data categories for rapid plasma shutdowns effected by massive gas and pellet injection. This work was supported in part by the US Department of Energy under DE-FC02-04ER54698. (author)