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Title: The causes of the disruptive tearing instabilities of the ITER Baseline Scenario in DIII-D

Abstract

Analysis of the evolving current density (J), pedestal and rotation profiles in a database of 200 ITER Baseline Scenario (IBS) demonstration discharges in the DIII-D tokamak identifies the current profile as a key determinant of the disruptive instability limiting both high and low torque operation of these q 95=3 plasmas. The m=2/n=1 tearing modes, occurring after several pressure-relaxation times, are linked to the shape of the current profile in the outer region of the plasma. The q=2 surface is located at r~0.78, near a minimum in J. A steeper "well" around the q=2 surface is correlated with the instabilities, and this finding is consistent for modes that occur both early (<1 T R) and late (>2 T R) on the β N flattop, at high and low input torque, for discharges with and without direct electron heating. Low rotation or differential rotation in the core plasmas is shown to not be the direct cause of the onset of these instabilities. The current profile trends identified in this work indicate that the modes limiting the Q=10 operation in the ITER demonstration plasmas are likely due to the slow evolution of the current profile, and reveal which shape of the current profilemore » is more prone to the 2/1 tearing instability.« less

Authors:
 [1];  [2];  [2];  [2];  [1];  [1]
  1. Columbia Univ., New York, NY (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1470983
Grant/Contract Number:  
[FC02-04ER54698; FG02-04ER54761]
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
[ Journal Volume: 58; Journal Issue: 10]; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ITER Baseline; stability; database; MHD stability; tearing stability; scenarios

Citation Formats

Turco, F., Luce, T. C., Solomon, W., Jackson, G., Navratil, G. A., and Hanson, J. M. The causes of the disruptive tearing instabilities of the ITER Baseline Scenario in DIII-D. United States: N. p., 2018. Web. doi:10.1088/1741-4326/aadbb5.
Turco, F., Luce, T. C., Solomon, W., Jackson, G., Navratil, G. A., & Hanson, J. M. The causes of the disruptive tearing instabilities of the ITER Baseline Scenario in DIII-D. United States. doi:10.1088/1741-4326/aadbb5.
Turco, F., Luce, T. C., Solomon, W., Jackson, G., Navratil, G. A., and Hanson, J. M. Tue . "The causes of the disruptive tearing instabilities of the ITER Baseline Scenario in DIII-D". United States. doi:10.1088/1741-4326/aadbb5. https://www.osti.gov/servlets/purl/1470983.
@article{osti_1470983,
title = {The causes of the disruptive tearing instabilities of the ITER Baseline Scenario in DIII-D},
author = {Turco, F. and Luce, T. C. and Solomon, W. and Jackson, G. and Navratil, G. A. and Hanson, J. M.},
abstractNote = {Analysis of the evolving current density (J), pedestal and rotation profiles in a database of 200 ITER Baseline Scenario (IBS) demonstration discharges in the DIII-D tokamak identifies the current profile as a key determinant of the disruptive instability limiting both high and low torque operation of these q95=3 plasmas. The m=2/n=1 tearing modes, occurring after several pressure-relaxation times, are linked to the shape of the current profile in the outer region of the plasma. The q=2 surface is located at r~0.78, near a minimum in J. A steeper "well" around the q=2 surface is correlated with the instabilities, and this finding is consistent for modes that occur both early (<1 TR) and late (>2 TR) on the βN flattop, at high and low input torque, for discharges with and without direct electron heating. Low rotation or differential rotation in the core plasmas is shown to not be the direct cause of the onset of these instabilities. The current profile trends identified in this work indicate that the modes limiting the Q=10 operation in the ITER demonstration plasmas are likely due to the slow evolution of the current profile, and reveal which shape of the current profile is more prone to the 2/1 tearing instability.},
doi = {10.1088/1741-4326/aadbb5},
journal = {Nuclear Fusion},
number = [10],
volume = [58],
place = {United States},
year = {2018},
month = {9}
}

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