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Title: Effect of thick blanket modules on neoclassical tearing mode locking in ITER

The rotation of m/n = 2/1 tearing modes can be slowed and stopped (i.e. locked) by eddy currents induced in resistive walls in conjunction with residual error fields that provide a final 'notch' point. This is a particular issue in ITER with large inertia and low applied torque (m and n are poloidal and toroidal mode numbers respectively). Previous estimates of tolerable 2/1 island widths in ITER found that the ITER electron cyclotron current drive (ECCD) system could catch and subdue such islands before they persisted long enough and grew large enough to lock. These estimates were based on a forecast of initial island rotation using the n = 1 resistive penetration time of the inner vacuum vessel wall and benchmarked to DIII-D high-rotation plasmas, However, rotating tearing modes in ITER will also induce eddy currents in the blanket as the effective first wall that can shield the inner vessel. The closer fitting blanket wall has a much shorter time constant and should allow several times smaller islands to lock several times faster in ITER than previously considered; this challenges the ECCD stabilization. Here, recent DIII-D ITER baseline scenario (IBS) plasmas with low rotation through small applied torque allow bettermore » modeling and scaling to ITER with the blanket as the first resistive wall.« less
Authors:
 [1] ;  [1] ;  [2]
  1. General Atomics, San Diego, CA (United States)
  2. Culham Science Centre, Abingdon (United Kingdom)
Publication Date:
Grant/Contract Number:
FC02-04ER54698
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 1; Related Information: R.J. La Haye, C. Paz-Soldan, Y.Q. Liu, "Effect of thick blanket modules on neoclassical tearing mode locking in ITER", Nucl. Fusion 57, 014004 (2017); Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
General Atomics, San Diego, CA (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Contributing Orgs:
CCFE, Culham Science Centre, Abingdon, OX14 3DB, UK
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tearing modes; locked modes; tokamak; ITER
OSTI Identifier:
1372085
Alternate Identifier(s):
OSTI ID: 1330919; OSTI ID: 1404937

La Haye, R. J., Paz-Soldan, C., and Liu, Y. Q.. Effect of thick blanket modules on neoclassical tearing mode locking in ITER. United States: N. p., Web. doi:10.1088/0029-5515/57/1/014004.
La Haye, R. J., Paz-Soldan, C., & Liu, Y. Q.. Effect of thick blanket modules on neoclassical tearing mode locking in ITER. United States. doi:10.1088/0029-5515/57/1/014004.
La Haye, R. J., Paz-Soldan, C., and Liu, Y. Q.. 2016. "Effect of thick blanket modules on neoclassical tearing mode locking in ITER". United States. doi:10.1088/0029-5515/57/1/014004. https://www.osti.gov/servlets/purl/1372085.
@article{osti_1372085,
title = {Effect of thick blanket modules on neoclassical tearing mode locking in ITER},
author = {La Haye, R. J. and Paz-Soldan, C. and Liu, Y. Q.},
abstractNote = {The rotation of m/n = 2/1 tearing modes can be slowed and stopped (i.e. locked) by eddy currents induced in resistive walls in conjunction with residual error fields that provide a final 'notch' point. This is a particular issue in ITER with large inertia and low applied torque (m and n are poloidal and toroidal mode numbers respectively). Previous estimates of tolerable 2/1 island widths in ITER found that the ITER electron cyclotron current drive (ECCD) system could catch and subdue such islands before they persisted long enough and grew large enough to lock. These estimates were based on a forecast of initial island rotation using the n = 1 resistive penetration time of the inner vacuum vessel wall and benchmarked to DIII-D high-rotation plasmas, However, rotating tearing modes in ITER will also induce eddy currents in the blanket as the effective first wall that can shield the inner vessel. The closer fitting blanket wall has a much shorter time constant and should allow several times smaller islands to lock several times faster in ITER than previously considered; this challenges the ECCD stabilization. Here, recent DIII-D ITER baseline scenario (IBS) plasmas with low rotation through small applied torque allow better modeling and scaling to ITER with the blanket as the first resistive wall.},
doi = {10.1088/0029-5515/57/1/014004},
journal = {Nuclear Fusion},
number = 1,
volume = 57,
place = {United States},
year = {2016},
month = {11}
}