DISRUPTION CHARACTERIZATION AND DATABASE ACTIVITIES FOR ITER

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 MDSplus-based IDDB infrastructure for collection and retrieval of disruption-relevant tokamak data, and (3) collection of a “version 1” data set from eight elongated-plasma tokamaks. Analysis of the current quench data provides a new recommendation about the lower bound on the plasma current decay time in ITER. Plans for further expansion of the scope and content of the IDDB have been identified. 1. Motivation and Mechanics Data on the expected characteristics of disruptions and on the nature and magnitude of disruption effects are needed for the design and functional validation of ITER components and systems. The applicable physics bases and samples of the then-available (circa 1996) data are described in Ref. [1], and considerations for extrapolation of that data to the then-current ITER design (R = 8.14 m, I = 21 MA) are given therein. Evolution of the ITER design to the present configuration ( R = 6.2 m, I = 15 MA) [2] and review of disruption-related design issues [3] provide motivation for improvement of the scope and quality of disruption data and for reconsideration of the means for extrapolating present data to ITER and beyond. In 2003, the representatives from the ITER International Team (IT) and the ITPA identified the need for new versions of the databases for plasma current quench rate and halo current magnitude and toroidal symmetry that were developed during the ITER Engineering Design Activities (EDA). This led to a plan to establish a new, ITPA-sanctioned International Disruption Database (IDDB), with a structure and user and public access principles that would parallel those of other existing ITPA databases (e.g., [4,5]). Features envisioned for the IDDB included the use of a modern scalable/expandable client-server based data management system (MDSplus [6]) and configuration of the database structure to allow for traceability of