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Title: Disruption mitigation studies in DIII-D

Data on the discharge behavior, thermal loads, halo currents, and runaway electrons have been obtained in disruptions on the DIII-D tokamak. These experiments have also evaluated techniques to mitigate the disruptions while minimizing runaway electron production. Experiments injecting cryogenic impurity killer pellets of neon and argon and massive amounts of helium gas have successfully reduced these disruption effects. The halo current generation, scaling, and mitigation are understood and are in good agreement with predictions of a semianalytic model. Results from killer pellet injection have been used to benchmark theoretical models of the pellet ablation and energy loss. Runaway electrons are often generated by the pellets and new runaway generation mechanisms, modifications of the standard Dreicer process, have been found to explain the runaways. Experiments with the massive helium gas puff have also effectively mitigated disruptions without the formation of runaway electrons that can occur with killer pellets.
Authors:
; ;  [1]
  1. General Atomics, San Diego, CA (United States) [and others
Publication Date:
OSTI Identifier:
319672
Report Number(s):
GA--A23019; CONF-981127--
ON: DE99001728; TRN: 99:003881
DOE Contract Number:
AC03-99ER54463;AC05-96OR22464;AC02-76CH03073;FG03-95ER54294
Resource Type:
Technical Report
Resource Relation:
Conference: 40. annual physics of plasmas meeting, APS Division of Plasma Physics, New Orleans, LA (United States), 16-20 Nov 1998; Other Information: PBD: Jan 1999
Research Org:
General Atomics, San Diego, CA (United States);Oak Ridge National Lab., TN (United States);Princeton Univ., NJ (United States);Univ. of California, Los Angeles, CA (United States)
Sponsoring Org:
USDOE Office of Energy Research, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; DOUBLET-3 DEVICE; PLASMA DISRUPTION; MITIGATION; RUNAWAY ELECTRONS; PLASMA IMPURITIES; ELECTRIC CURRENTS; PLASMA SIMULATION; EXPERIMENTAL DATA