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Title: Characterization of MHD activity and its influence on radiation asymmetries during massive gas injection in DIII-D

Measurements from the DIII-D tokamak show that toroidal radiation asymmetries during fast shutdown by massive gas injection (MGI) are largely driven by n = 1 magnetohydrodynamic modes during the thermal quench. The phenomenology of these modes, which are driven unstable by pro le changes as the thermal energy is quenched, is described based on detailed magnetic measurements. Here, the toroidal evolution of the dominantly n = 1 perturbation is understood to be a function of three parameters: the location of the MGI port, pre-MGI plasma rotation, and n = 1 error elds. Here, the resulting level of radiation asymmetry in these DIII-D plasmas is modest, with a toroidal peaking factor (TPF) of 1:2 ± 0:1 for the total thermal quench energy and 1:4 ± 0:3 for the peak radiated power, both of which are below the estimated limit for ITER (TPF ≈ 2).
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of California San Diego, La Jolla, CA (United States)
Publication Date:
Grant/Contract Number:
FC02-04ER54698; AC05-00OR22725; FG02-07ER54609
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 55; Journal Issue: 7; Journal ID: ISSN 0029-5515
IOP Science
Research Org:
General Atomics, San Diego, CA (United States)
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Country of Publication:
United States
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; disruption mitigation; massive gas injection; radiation asymmetry
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1238886