Solar energetic particle drifts in the Parker spiral

Dalla, Silvia orcid iconORCID: 0000-0002-7837-5780, Marsh, M.S., Kelly, J. and Laitinen, T. orcid iconORCID: 0000-0002-7719-7783 (2013) Solar energetic particle drifts in the Parker spiral. Journal of Geophysical Research: Space Physics, 118 (10). pp. 5979-5985. ISSN 21699380

Full text not available from this repository.

Official URL:


Drifts in the Parker spiral interplanetary magnetic field are known to be an important component in the propagation of galactic cosmic rays, while they are thought to be negligible for solar energetic particles (SEPs). As a result, they have so far been ignored in SEP propagation modeling and data analysis. We examine drift velocities in the Parker spiral within single particle first-order adiabatic theory, in a local coordinate system with an axis parallel to the magnetic field. We show that, in the presence of scattering in interplanetary space, protons at the high end of the SEP energy range experience significant gradient and curvature drift. In the scatter-free case, drift due to magnetic field curvature is present. The magnitude of drift velocity increases by more than an order of magnitude at high heliographic latitudes compared to near the ecliptic; it has a strong dependence on radial distance r from the Sun, reaching a maximum at r˜1 AU at low heliolatitudes and r˜10 AU at high heliolatitudes. Due to the mass over charge dependence of drift velocities, the effect of drift for partially ionized SEP heavy ions is stronger than for protons. Drift is therefore likely to be a considerable source of cross-field transport for high-energy SEPs

Repository Staff Only: item control page