Solar Wind Turbulence from 1 to 45 au. II. Analysis of Inertial-range Fluctuations Using Voyager and ACE Observations

Abstract

We examine both Voyager and Advanced Composition Explorer magnetic field measurements at frequencies that characterize the inertial range using traditional polarization techniques that are designed to characterize plasma waves. Although we find good agreement with both the anticipated spectral index of the power spectrum and the scaling of magnetic power with heliocentric distance, we do not find that the polarization analyses yield results that can be readily described by plasma wave theory. The fluctuations are not circularly polarized and there is a markedly reduced coherence between the components of the fluctuation. The degree of polarization is also generally low, although not as low as the coherence, and the minimum variance direction is essentially random. We conclude that traditional plasma wave theory may not offer a good description for inertial-range fluctuations.