Analysis of MHD harmonic modes from the novel tangential X-ray diagnostic in EAST tokamak
Institute of Plasma Physics, Chinese Academy of Science - Hefei 230031, China
Accepted: 8 March 2011
The magnetohydrodynamics (MHD) harmonic modes as well as the underlying physics have been investigated in detail by applications of the Hilbert-Huang transform (HHT), higher-order spectrum (HOS) analysis and Fourier transform (FT), based on the novel tangential X-ray (TX) diagnostic (Li E. et al., Rev. Sci. Instrum., 81 (2010) 106102). Those signal process methods were applied to a rotating m/n = 2/1 magnetic island, and it was found that its second-order harmonic m/n = 4/2 appearing in FT spectrum (m, n are poloidal and toroidal mode numbers, respectively) was not an intrinsic mode, but a measure of distortion of the saturated magnetic island m/n = 2/1.
PACS: 07.05.Kf – Data analysis: algorithms and implementation; data management / 52.30.Cv – Magnetohydrodynamics (including electron magnetohydrodynamics) / 52.55.Fa – Tokamaks, spherical tokamaks
© EPLA, 2011