Accession Number:

AD0614100

Title:

AN INTERPLANETARY DIFFUSION MODEL FOR THE TIME BEHAVIOR OF INTENSITY IN A SOLAR COSMIC RAY EVENT,

Descriptive Note:

Corporate Author:

IOWA STATE UNIV IOWA CITY

Personal Author(s):

Report Date:

1965-04-01

Pagination or Media Count:

63.0

Abstract:

It is found possible to give a coherent interpretation of the time history of the intensity of several solar cosmic ray events in terms of a unified interplanetary diffusion model which assumes that the diffusion coeffieient D M r to the B power, where r is the heliocentric radial distance and M and B are parameters, which may be dependent on particle energy E. The model is particularly successful in accounting for the decay phases. For the September 28, 1961 event M varies as E to the 0.33 power and, assuming spherical geometry, B is equal to one for 55 E 500 MeV and decreases rapidly at lower energies. At r 1 A.U. the mean free path lambda is about 0.081 A.U. for E 200 MeV and 0.15 for E 23 MeV. The energy dependences of B and lambda suggest 0.006 A.U. as the order of magnitude of the scale size of irregularities in the interplanetary magnetic field. The source spectrum is inferred. The possibility of non-spherical geometry of diffusion is considered, as is the implication of the results with respect to the solar modulation of galactic cosmic radiation. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE