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

Journal Article · Thu Nov 03 00:00:00 EDT 2016 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/57/1/014004· OSTI ID:1372085

La Haye, R. J. ^[1]; Paz-Soldan, C. ^[1]; Liu, Y. Q. ^[2]

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1. General Atomics, San Diego, CA (United States)
2. Culham Science Centre, Abingdon (United Kingdom)

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. 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.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Contributing Organization: CCFE, Culham Science Centre, Abingdon, OX14 3DB, UK
• Grant/Contract Number: FC02-04ER54698
• OSTI ID: 1372085
• Alternate ID(s): OSTI ID: 1330919; OSTI ID: 1404937
• Journal Information: Nuclear Fusion, Vol. 57, 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); ISSN 0029-5515
• Publisher: IOP Science
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
tearing modes
locked modes
tokamak
ITER