Problems Related to Interplanetary Matter (1961) / Chapter Skim
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LOWER ENERGY COSMIC RAYS AND THE SOLAR CYCLE
LOWER ENERGY COSMIC RAYS AND THE SOLAR CYCLE
Pages 58-62
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From page 58... ...
, which may produce spallation nuclides in meteorites, is strongly influenced by solar phenomena. On the one hand one does observe striking changes in the flux and energy spectrum of the galactic cosmic radiation which are correlated with the 11-year solar activity cycle or with single solar flares (Forbush decreases)
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From page 59... ...
the energy spectrum of the high energy particles was measured to go roughly as E-". On the basis of radionoise absorption data and several months of satellite and space probe observations one may estimate the frequency of the occurrence of solar particle emission during the past maximum of solar activity.
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From page 60... ...
, due to the fact that incoming charged particles in the Mev to several Bev range cannot penetrate the shock barrier, and the galactic cosmic rays continue to be excluded until the shock waves have finally been damped out by particle collisions over a period of days or weeks. A slight increase in galactic cosmic radiation prior to the onset of the Forbush decrease is expected in this model and has been noted several times.
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From page 61... ...
There are a few points in Parker's theory which are of special importance in relating the cosmic ray flux to nucleogenesis in the meteorites. First, the meteorites would be expected to receive a full flux of galactic cosmic radiation during whatever time their orbits were outside the instability barrier, regardless of the phase of the solar cycle.
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From page 62... ...
If so, any shock waves propagating outward would also eventually present a shock front directed inward, toward the Sun, and should result in anisotropies in the galactic cosmic ray flux some days after a flare. Van Allen: It is not strictly necessary that the lines-of-force be closed for the divergence of ^to vanish, provided the lines-of-force constitute a sufficiently complicated network.
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