Turbulent polar heliospheric fields

Abstract

Recent observational studies of interplanetary field fluctuations and MHD simulation results are used to suggest that the turbulent evolution of the fields over the solar poles leads to a state intermediate between the large fields of the static limit and the small fields given by 'saturation' (deltaB/B = about 1). In particular, assuming the strength of the coronal hole sources of fluctuations are similar in all solar regions, the polar fluctuations in the outer heliosphere are likely to be nearly isotropic, with amplitudes somewhat smaller than those predicted by the WKB extrapolation from 1 AU in the ecliptic plane.