Multichannel fluctuation data analysis by the singular value decomposition method : Application to MHD modes in JETFunded under: FP2-FUSION 10C
The spatial structure and temporal evolution of coherent MHD modes in fusion plasma devices have been inferred from the experimental signals by using spectral techniques. Considering the data as a collection of n-dimensional discrete time series x(i)(t) permits the use of a signal processing method based on the singular value decomposition (SVD) of a rectangular matrix. This paper shows that, whereas the SVD is equivalent to the discrete Fourier transform in the case of travelling sinusoidal waves, in more realistic cases it is a clear improvement on the spectral methods, since it disentangles the poloidal structure without a priori knowledge. Various applications of SVD, first on artificial signals and then on magnetic and SXR signals detected in the JET tokamak in several plasma regimes, are shown to illustrate the power and limitations of the method.
Bibliographic Reference: Report: JET-P(92)01 EN (1992) 19 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199310240 / Last updated on: 1994-11-29
Original language: en
Available languages: en