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Title: Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D

Intentionally triggered upward and downward vertical displacement events (VDEs) leading to disruptions were pre-emptively mitigated with neon massive gas injection (MGI) coming from either above or below the plasma. Global indicators of disruption mitigation effectiveness (conducted heat loads, radiated power, and vessel motion) do not show a clear improvement when mitigating with the gas jet located closer to the VDE impact area. A clear trend of improved mitigation is observed for earlier MGI timing relative to the VDE impact time. The plasma edge magnetic perturbation is seen to lock to a preferential phase during the VDE thermal quench, but this phase is not clearly matched by preliminary attempts to fit to the conducted heat load phase. Clear indications of plasma infra-red (IR) emission are observed both before and during the disruptions. This IR emission can affect calculation of disruption heat loads; here, the time decay of post-disruption IR signals is used to correct for this effect.
Authors:
;  [1] ; ;  [2] ; ;  [3] ;  [4]
  1. University of California-San Diego, La Jolla, California 92093 (United States)
  2. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
  3. General Atomics, San Diego, California 92186 (United States)
  4. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22486433
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DISPLACEMENT FLUIDS; DISTURBANCES; DOUBLET-3 DEVICE; GAS INJECTION; HEATING LOAD; INFRARED RADIATION; JETS; MITIGATION; NEON; PLASMA; SIGNALS