Cross-field diffusion of electrons in tangled magnetic fields and implications for coronal fine structure

High-resolution images of the solar corona suggest that some degree of tangling exists in the coronal magnetic structure. We show that a very low level of such magnetic tangling is sufficient for Rechester-Rosenbluth diffusion to be the dominant cross-field plasma transport mechanism. This diffusive process, which moves particles rapidly across the field on tangled field lines, is thus likely to be a governing mechanism in controlling plasma structure in the direction perpendicular to the magnetic field. We generate model coronal loops with cross-field dimensions governed by Rechester-Rosenbluth diffusion and show that the cross-field transport is consistent with the observed widths of coronal magnetic loops. Together with observed loop morphology, these calculations allow us to constrain the degree of magnetic field disorder likely to be present in the corona, and in particular the degree of tangling as invoked in discussions of coronal heating.