Perpendicular transport of charged particles in the heliosphere

Abstract

We investigate spatial fractal structures of the Heliospheric Magnetic Field, using Ulysses magnetic field data. Fractal parameters of these structures are determined during the first off-ecliptic orbit of Ulysses. We construct a model magnetic field, which shows similar fractal characteristics than the magnetic field measurements. In the model field we also include intermittent turbulence, consistent with observations. Mixing of the field lines, leading to fractal structures are considered. Trajectories of test particles are followed in the model field, and the perpendicular diffusion coefficient is determined. Investigation of particle propagation shows a substantial enhancement of the perpendicular diffusion coefficient, due to field line mixing.