Meeting abstract

AGU Fall Meeting, San Francisco, 15-19 December 1996

Abstract:
A variety of techniques are available for analysing turbulent processes. We discuss Fourier, structure function and wavelet methods, highlighting the advantages of each technique, and present results of analyses of Ulysses magnetic field observations. We discuss errors and uncertainties associated with structure function calculations and describe a novel criterion for rejecting unreliable results. In practice, uncertainties place strong limits on the highest reliable structure function moment, which is typically 4 to 6. After rejecting unreliable results, we compare the observations with several intermittent turbulence models and demonstrate that the p model best describes the fluctuations, in agreement with terrestrial turbulent flows ™ although heliospheric turbulence appears to be more intermittent. In addition, we attempt to discriminate between Kolmogorov and Kraichnan cascades, while allowing for the complication of strong intermittency in the inertial range, using both structure function and wavelet techniques.