Phenomenological comparison of magnetic and electrostatic fluctuations in the Macrotor tokamak

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Abstract
Probe measurements of magnetic and electrostatic fluctuations in Macrotor are compared. Attention is concentrated on small-scale fluctuations which lie in the frequency range above the usual low-frequency Mirnov oscillations. In this range, 20 kHz < f > 125 kHz, the spectra of and are similar; the radial profile of ñ/n is, however, peaked toward the outside while that of r is peaked toward the centre, and no local cross-correlation between and has been detected. The radial correlation length of is smaller than that for r (both being much smaller than the minor radius), but the poloidal correlation lengths of p and are similar. Both and fluctuations rotate in the electron diamagnetic drift direction. The spectra are roughly invariant to an increase in density; however, the magnitude of ñ/n decreases with density while that of r remains unchanged. No connection between these fluctuations and anomalous transport has been established.