Examination of fluctuations of temperature and their correlation with fluctuations of density at W7-AS
The properties of the local fluctuations of temperature in nuclear plasma were examined in order to determine how they correlate with fluctuations of density. The crossed sightline correlation technique was applied, and compared to the single sightline technique by adding pairs of channels. The diffusive and the turbulent fluctuation component clearly appeared separately in the spectrum. Simultaneous measurement by means of reflectometry and ECE-correlation radiometry showed a significant coherence of 10-30% for the area of frequencies of the turbulent fluctuation component over 30 kHz. An increase in distance between ECE-channels and cut off position led to a decrease in coherence, which, simplified, means a correlation of the same phase between fluctuations of temperature and of density. Yet the fluctuations in the reflectometry signal are partially masked; consequently the degree of coherence is likely to be significantly higher than the value above.
Bibliographic Reference: Report: IPP III/229 DE (1998) 125pp.
Availability: Available from the Max-Planck Institut für Plasmaphysik, 85748 Garching bei München (DE)
Record Number: 199810610 / Last updated on: 1998-05-26
Original language: de
Available languages: de