Spectral and Correlation Analysis of Soft X-ray Signals from the JET Tokamak
Soft X-rays emitted from a fusion plasma can be used to diagnose and interpret magnetohydrodynamic (MHD) and other plasma activities. Tomographic methods are commonly applied to perform analysis of the measured soft X-ray intensities. However, fluctuation analysis has recently been proposed as a complementary method to tomography. In this paper we report on the results of an investigation of soft X-ray data using correlation and spectral analysis. The seven measurements analysed were made by the Joint European Torus (JET) Joint Undertaking using their old soft X-ray measurement system. Auto spectra and phase relations were evaluated from the measured signals and the results show the spectral structure and the distribution of the line integrated periodic MHD modes as functions of lines of sight. The fundamental mode with poloidal and toroidal mode numbers m=n=1 was identified in several measurements. The corresponding frequency and toroidal rotation velocity was determined. Higher order modes were also observed and identified. Further, simple model calculations were performed and the results compared with evaluated auto spectra.
Bibliographic Reference: Report JET-P(96)03 EN (1996) 5pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199610689 / Last updated on: 1996-06-21
Original language: en
Available languages: en