Fluctuation studies of the edge plasma on the RENTOR tokamak

Two Langmuir probes with a separation of 0.540 cm were used to measure poloidal and toroidal potential and density fluctuations in the 0-200 kHz range in the edge region of the Rensselaer Polytechnic Institute research tokamak RENTOR. RENTOR is a small device of major radius 45 cm, minor radius 15 cm, toroidal magnetic field 3.5 kG, typical pulse length 10 msec, loop voltage 5V, peak plasma current 20 kA, peak electron density → 10/sup 12/ cm/sup -3/ and peak electron temperature 0.1 keV. Quantities of particular interest such as n/sup --//n, PHI/sup --// PHI, ePHI/sup --//k/sub b/T and [ePHI/sup --//κ/sub b/T]/[n/sup --//n], were examined as a function of radius for both poloidal and toroidal fluctuations. The phase, coherence, autopower, and κ(w) spectra were determined for the poloidal, toroidal, and radial directions and an estimate of the outward-induced particle transport in the edge region was made. These results will be compared with similar measurements made with the heavy ion beam probe