MEASUREMENTS OF NONLINEAR ENERGY-TRANSFER IN TURBULENCE IN THE TOKAMAK FUSION TEST REACTOR

The application of anew bispectral analysis technique to density fluct uation measurements in the core of the Tokamak Fusion Test Reactor ind icates that the peak in the autopower spectrum usually lies in a regio n of linear stability. Large changes in the linear and nonlinear chara cteristics of the turbulence are observed as the plasma toroidal rotat ion and/or confinement properties are varied, while estimates of the t urbulence-driven diffusivity varies only slightly with rotation. These observations are consistent with the operation of a global organizing property that may be related to the observation of Bohm-like scaling of ion thermal transport.