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论文类型：期刊论文

发表时间：2018-05-01

发表刊物：PLASMA PHYSICS AND CONTROLLED FUSION

收录刊物：SCIE、EI

卷号：60

期号：5

ISSN号：0741-3335

关键字：intrinsic error field correction; EAST; simulation

摘要：The m/n - 2/1 resonant vacuum error field (EF) in the EAST tokamak experiments, inferred from the compass coil current amplitude and phase scan for mode locking, was found to depend on the parity between the upper and lower rows of the EF correction (EFC) coils (Wang et al 2016 Nucl. Fusion 56 066011). Here m and n are the poloidal and toroidal harmonic numbers in a torus, respectively. This experimental observation implies that the compass scan results cannot be simply interpreted as reflecting the true intrinsic EF. This work aims at understanding this puzzle, based on toroidal modeling of the EFC plasma discharge in EAST using the MARS- F code (Liu et al 2000 Phys. Plasmas 7 3681). By varying the amplitude and phase of the assumed n - 1 intrinsic vacuum EF with different poloidal spectra, and by computing the plasma response to the assumed EF, the compass scan predicted 2/1 EF, based on minimizing the computed resonant electromagnetic torque, can be made to match well with that of the EFC experiments using both even and odd parity coils. Moreover, the compass scan predicted vacuum EFs are found to be significantly differing from the true intrinsic EF used as input to the MARSF code. While the puzzling result remains to be fully resolved, the results from this study offer an improved understanding of the EFC experiments and the compass scan technique for determining the intrinsic resonant EF.