STATISTICALLY ROBUST LINEAR AND NONLINEAR WAVELET ANALYSIS APPLIED TOPLASMA EDGE TURBULENCE

The analysis of turbulence requires adequate analysis tools. In partic ular, two general properties of turbulence make the application of sta ndard analysis tools (spectral analysis) difficult: (1) intermittency, which causes the characteristics of turbulence to change on a relativ ely short time scale, implies that analysis tools must not integrate o ver time scales longer than the intermittent time scale; (2) nonlinear ity, a basic property of all numerical models of chaos and turbulence, requires specially adapted tools for its proper detection. In the pre sent work, we develop a statistically stable formalism for the applica tion of wavelet analysis techniques to the analysis of turbulence. We apply these techniques to the analysis of Langmuir probe data in the p lasma edge region of the TJ-IU Torsatron. We draw some tentative concl usions about radial correlation lengths. Further, we analyze the L/H t ransition at the Continous Current Tokamak and reconstruct a radial pr ofile of bicoherence in the plasma edge in the H-mode. (C) 1997 Americ an Institute of Physics.