Study of the spectrum effect on the threshold of resonant magnetic perturbation penetration on J-TEXT

• Published in: Plasma science & technology 2022-12, Vol.24 (12), p.124002
• Main Authors: MAO, Feiyue, WANG, Nengchao, HUANG, Zhuo, REN, Zhengkang, ZHOU, Song, SHEN, Chengshuo, ZHANG, Xiaoyi, HE, Ying, ZHANG, Qi, JIA, Ruo, ZHAO, Chuanxu, LI, Yangbo, HU, Bo, LI, Da, BALA, Abba Alhaji, CHEN, Zhipeng, CHEN, Zhongyong, YANG, Zhoujun, LIANG, Yunfeng, DING, Yonghua, PAN, Yuan
• Format: Article
• Language: English
• Subjects: error field; mode penetration; resonant magnetic perturbation; spectrum analysis; tokamak
• ISSN: 1009-0630; 2058-6272
• DOI: 10.1088/2058-6272/ac9f2e

The spectrum effect on the penetration of resonant magnetic perturbation (RMP) is studied with upgraded in-vessel RMP coils on J-TEXT. The poloidal spectrum of the RMP field, especially the amplitudes of 2/1 and 3/1 components, can be varied by the phase difference between the upper and lower coil rows, Δ ϕ  =  ϕ top − ϕ bottom , where ϕ top and ϕ bottom are the toroidal phases of the n  = 1 field of each coil row. The type of RMP penetration is found to be related to Δ ϕ , including the RMP penetration of either 2/1 or 3/1 RMP and the successive penetrations of 3/1 RMP followed by the 2/1 RMP. For cases with penetration of only one RMP component, the penetration thresholds measured by the corresponding resonant component are close for various Δ ϕ . However, the 2/1 RMP penetration threshold is significantly reduced if the 3/1 locked island is formed in advance. The changes in the rotation profile due to 3/1 locked island formation could partially contribute to the reduction of the 2/1 thresholds.