Singular Value Decomposition Analysis of Multichannel Electron Cyclotron Emission Signals of Tokamak Plasma
A. Isayama, N. Iwama, Yohsuke Hosoda, S. Satake, N Isei, S. Ishida, Masayasu Satō · Japanese Journal of Applied Physics · 2003
Singular value decomposition (SVD) was applied to multichannel signals obtained by an electron cyclotron emission diagnostic system in the JT-60U tokamak. As a result, on grating polychromator signals, the equilibrium and perturbative terms of electron temperature profile were successfully separated, and the structure of a magnetic island produced by the tearing mode was revealed. By neglecting the components of small singular values, the noise component of the signals was removed to improve the signal-to-noise ratio while conserving well the pulse-like waveforms. The usefulness of the SVD-based spectral analysis is shown by a typical set of signal waveforms.