Amplitude of solar wind density turbulence from 10 to 45 R⊙

Abstract

We report on the amplitude of the density turbulence spectrum ( urn:x-wiley:jgra:media:jgra53108:jgra53108-math-0001) and the density modulation index (δN/N) in the solar wind between 10 and 45R⊙. We derive these quantities using a structure function that is observationally constrained by occultation observations of the Crab nebula made in 2011 and 2013 and similar observations published earlier. We use the most general form of the structure function, together with currently used prescriptions for the inner/dissipation scale of the turbulence spectrum. Our work yields a comprehensive picture (a) of the manner in which urn:x-wiley:jgra:media:jgra53108:jgra53108-math-0002 and δN/N vary with heliocentric distance in the solar wind and (b) of the solar cycle dependence of these quantities.