Transport across complex magnetic environment

It is well known that the rich, highly complicated field configurations of the Heliospheric Magnetic Field has an essential effect on the cross-field propagation of charged particles of relatively low rigidity. In this process the field line separation is the most significant factor of the magnetic structure. The aim of this paper is to develop a framework, in which the particle transport can be investigated for various types of field-line separation. It turns out that the presence of any diffusive cross-field motion of the particles, even if it is arbitrarily small, can wash out most of the details belonging to a specific field line separation model. In that case the overall cross-field motion is forced to become diffusive, irrespectively of the type of the field line spreading, whether this spreading is diffusive, or even non-diffusive in nature. For the various separation models the expressions derived are very similar.