SOFT X-RAY EMISSION FLUCTUATIONS IN THE HBTX1A REVERSED FIELD PINCH
An array of silicon surface barrier diodes and statistical analysis techniques have been used to study X-ray emission fluctuations in the HBTXIA Reversed Field Pinch. Despite the apparent randomness displayed by the signals it is shown that for frequencies less or about 30 kHz the dominant instabilities are global and have poloidal mode number m + z < 0 and 1. The radial profile of these modes is reconstructed and their power spectrum calculated. By using single detectors displayed in the toroidal direction it is seen that the m + z < 0 instabilities have long toroidal wavelength (n +- 0) and do not propagate in this direction, whereas the m + z < 1 modes are n >> 1. Local turbulence becomes the dominant component at higher frequencies; even so correlation parallel to toroidal direction is shown to be much longer than across. Correlating the X-ray diodes with magnetic edge coils enables a direct comparison of the two types of fluctuations and shows that one of the m + z < 0 modes propagates radially outwards.
Bibliographic Reference: WRITE TO THE LIBRARIAN, UKAEA, CULHAM LABORATORY, ABINGDON, OXON. OX14 3DB (UK), MENTIONING REPORT CLM-P722, 1984
Record Number: 1989123050800 / Last updated on: 1987-01-01
Available languages: en