The spectrum of magnetic field irregularities in the solar corona and in interplanetary space Original Research Article

Results are presented of a spectral analysis of Faraday rotation fluctuations observed during the solar occultations of the Helios spacecraft. The temporal spectra of Faraday rotation fluctuations in the frequency range between 10−3 Hz and 10−2 Hz usually assume the form of a power law. The power-law exponent is ⋍1.6 at heliocentric distances 3 R⊙ < r < 6 R⊙ (R⊙ = solar radius) and ⋍1.1 at distances 6 R⊙ < r < 12 R⊙. The Faraday rotation data are compared with in situ measurements of magnetic field fluctuations in the range of solar distances 0.3 < r < 1 AU.