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The October 22, 1989, solar cosmic ray enhancement: An analysis of the anisotropy and spectral characteristics


Cramp, JL and Duldig, ML and Fluckiger, EO and Humble, JE and Shea, MA and Smart, DF, The October 22, 1989, solar cosmic ray enhancement: An analysis of the anisotropy and spectral characteristics, Journal of Geophysical Research-Space Physics, 102, (A11) pp. 24237-24248. ISSN 0148-0227 (1997) [Refereed Article]

DOI: doi:10.1029/97JA01947


A 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.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:High energy astrophysics and galactic cosmic rays
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Cramp, JL (Ms Jennifer Cramp)
UTAS Author:Duldig, ML (Dr Marc Duldig)
UTAS Author:Humble, JE (Dr John Humble)
ID Code:10167
Year Published:1997
Web of Science® Times Cited:82
Deposited By:Physics
Deposited On:1997-08-01
Last Modified:2011-11-07

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