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Title: Passive runaway electron suppression in tokamak disruptions

Runaway electrons created in disruptions pose a serious problem for tokamaks with large current. It would be desirable to have a runaway electron suppression method which is passive, i.e., a method that does not rely on an uncertain disruption prediction system. One option is to let the large electric field inherent in the disruption drive helical currents in the wall. This would create ergodic regions in the plasma and increase the runaway losses. Whether these regions appear at a suitable time and place to affect the formation of the runaway beam depends on disruption parameters, such as electron temperature and density. We find that it is difficult to ergodize the central plasma before a beam of runaway current has formed. However, the ergodic outer region will make the Ohmic current profile contract, which can lead to instabilities that yield large runaway electron losses.
Authors:
;  [1] ;  [2] ;  [3]
  1. Max-Planck/Princeton Center for Plasma Physics, Max-Planck-Institut für Plasmaphysik, 17491 Greifswald (Germany)
  2. Max-Planck/Princeton Center for Plasma Physics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22227950
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 7; Other Information: (c) 2013 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELECTRIC CURRENTS; ELECTRIC FIELDS; ELECTRON TEMPERATURE; ION TEMPERATURE; PLASMA CONFINEMENT; PLASMA DENSITY; PLASMA DISRUPTION; PLASMA INSTABILITY; PLASMA RADIAL PROFILES; RUNAWAY ELECTRONS; TOKAMAK DEVICES