Cosmic-Ray Transport in the Presence of a Fisk-type Heliospheric Magnetic Field: Investigating the Influence of Drift

Abstract Drifts due to the gradients in, and curvatures of, the heliospheric magnetic field (HMF) play a significant role in the transport of galactic cosmic rays (GCRs) in the heliosphere. Although this has been well studied for the Parker HMF, the influence of Fisk-type fields, with their unique geometry, has hitherto received less attention. Here, drift velocity profiles computed for a Schwadron–Parker hybrid field are compared with those for a purely Parkerian field. Furthermore, the influence of this field on GCR modulation, as computed with a 3D, ab initio, modulation model, is investigated. Globally, the differences between the computed intensities are small. Nevertheless, local measures, such as azimuthal variations in the GCR intensities, show a significant influence of the Schwadron–Parker hybrid field on GCR transport.