Measurements of Nonlinear Energy Transfer in Turbulence in the Tokamak Fusion Test Reactor

The application of a new bispectral analysis technique to density fluctuation measurements in the core of the Tokamak Fusion Test Reactor indicates that the peak in the autopower spectrum usually lies in a region of linear stability. Large changes in the linear and nonlinear characteristics of the turbulence are observed as the plasma toroidal rotation and/or confinement properties are varied, while estimates of the turbulence-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.