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

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First Author:Feiyue Mao

Correspondence Author:Nengchao Wang

Journal:Plasma Science and Technology

Volume:24

Issue:12

Page Number:124002

DOI number:10.1088/2058-6272/ac9f2e

Date of Publication:2022-11-29

Abstract: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, Δϕ = 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 Δϕ, 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 Δϕ. 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.

Links to published journals:https://doi.org/10.1088/2058-6272/ac9f2e