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The October 22, 1989, solar cosmic ray enhancement: An analysis of the anisotropy and spectral characteristics
journal contribution
posted on 2023-05-16, 10:27 authored by Cramp, JL, Marcus DuldigMarcus Duldig, Fluckiger, EO, John Humble, Shea, MA, Smart, DFA solar cosmic ray ground-level enhancement was observed, at Earth on October 22, 1989, with an extremely anisotropic onset. On the basis of neutron monitor data we have derived the arrival directions, spectra, and pitch angle distributions of the greater than or equal to 1 GV solar protons. The results indicate an extended time period during which high-energy particles propagated past Earth with minimal scattering in the local interplanetary medium. The deduced pitch angle distributions of the particles propagating from the Sun show a relatively slow evolution from a focused particle flux, even though there are dramatic changes in the observed intensity-time profiles. Strong evidence is found that reverse scattering of particles beyond Earth resulted in bidirectional flow along the local interplanetary magnetic field during the second phase of the event.
History
Publication title
Journal of Geophysical Research-Space PhysicsVolume
102Issue
A11Pagination
24237-24248ISSN
0148-0227Department/School
School of Natural SciencesPublisher
American Geophysical UnionPlace of publication
WashingtonRepository Status
- Restricted