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Title: Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events

Abstract

This paper discusses the use of radio frequency (RF) current drive to stabilize large islands, focusing on nonlinear effects that appear when relatively high powers are used to stabilize large islands. We are interested in developing a capability to stabilize large islands via RF driven currents to avoid the need for mitigation to the extent possible. As tokamaks are designed and built with increasing levels of stored energy in the plasma, disruptions become increasingly dangerous. It has been reported that 95% of the disruptions in the Joint European Torus tokamak with the ITER-like wall are preceded by the growth of large locked islands. These large islands are mostly produced by off-normal events other than neoclassical tearing modes. This paper presents theory and modeling for a nonlinear “RF current condensation” effect that can concentrate the RF driven current near the center of a large island, thereby increasing the efficiency of the stabilization. A nonlinear shadowing effect can hinder the stabilization of islands if the aiming of the ray trajectories does not properly consider the nonlinear effects.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1];  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1810620
Alternate Identifier(s):
OSTI ID: 1970654
Grant/Contract Number:  
FG02-91ER54109; SC0018090; AC02-09CH11466; SC0016072
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 28; Journal Issue: 4; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Reiman, A. H., Bertelli, N., Fisch, N. J., Frank, S. J., Jin, S., Nies, R., and Rodriguez, E. Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events. United States: N. p., 2021. Web. doi:10.1063/5.0042479.
Reiman, A. H., Bertelli, N., Fisch, N. J., Frank, S. J., Jin, S., Nies, R., & Rodriguez, E. Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events. United States. https://doi.org/10.1063/5.0042479
Reiman, A. H., Bertelli, N., Fisch, N. J., Frank, S. J., Jin, S., Nies, R., and Rodriguez, E. Wed . "Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events". United States. https://doi.org/10.1063/5.0042479. https://www.osti.gov/servlets/purl/1810620.
@article{osti_1810620,
title = {Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events},
author = {Reiman, A. H. and Bertelli, N. and Fisch, N. J. and Frank, S. J. and Jin, S. and Nies, R. and Rodriguez, E.},
abstractNote = {This paper discusses the use of radio frequency (RF) current drive to stabilize large islands, focusing on nonlinear effects that appear when relatively high powers are used to stabilize large islands. We are interested in developing a capability to stabilize large islands via RF driven currents to avoid the need for mitigation to the extent possible. As tokamaks are designed and built with increasing levels of stored energy in the plasma, disruptions become increasingly dangerous. It has been reported that 95% of the disruptions in the Joint European Torus tokamak with the ITER-like wall are preceded by the growth of large locked islands. These large islands are mostly produced by off-normal events other than neoclassical tearing modes. This paper presents theory and modeling for a nonlinear “RF current condensation” effect that can concentrate the RF driven current near the center of a large island, thereby increasing the efficiency of the stabilization. A nonlinear shadowing effect can hinder the stabilization of islands if the aiming of the ray trajectories does not properly consider the nonlinear effects.},
doi = {10.1063/5.0042479},
journal = {Physics of Plasmas},
number = 4,
volume = 28,
place = {United States},
year = {Wed Apr 21 00:00:00 EDT 2021},
month = {Wed Apr 21 00:00:00 EDT 2021}
}

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