Structure of density fluctuations near the sun deduced from Pioneer-6 spectral broadening measurements

In this paper we present an analysis of the spectral broadening of monochromatic radio waves by density fluctuations near the Sun using the parabolic equation method. Application of the analysis to the 1968 Pioneer-6 spectral broadening observations yields indirect measurements of the density spectrum within 14 R/sub sun/ of the Sun. For spatial wavenumbers kappaapproximately-greater-than8.4 x 10-3 km-1, the three-dimensional density spectrum is found to be close to the Kolmogorov spectrum (power law with spectral index p=11/3) and is consistent with the IPS (interplanetary scintillations) and in situ spacecraft measurements farther from the Sun. The magnitude of the density spectrum increases but the shape of the density spectrum remains the same during the ''solar events'' marked by increases in the bandwidth