PERPENDICULAR DIFFUSION AND DRIFT AT INTERMEDIATE COSMIC-RAY ENERGIES

We present a new derivation of perpendicular diffusion and drift coeff icients, based on the Taylor-Green-Kubo equation and physical argument s as to the form of the particle velocity correlation function. In con trast to previous derivations, which are restricted to particle rigidi ties greater than 4 GV for typical conditions at 1 AU, our derivation is valid for intermediate-energy, as well as high-energy, cosmic rays. Our results provide a natural explanation for several hitherto puzzli ng observations, including (1) the form of the perpendicular diffusion coefficient derived from measurements of anomalous cosmic rays, (2) t he fact that drift models often describe observations better when drif ts are reduced, and (3) the ''CR-B'' relation, which associates cosmic -ray modulation with enhanced magnetic fields in merged interaction re gions.