GEOMAGNETIC AND INTERPLANETARY EFFECTS ON SOLAR COSMIC RAYS
The energy spectra and the time variations for many of the larger solar cosmic ray events from 1958 to the present have been directiy measured with balloons, satellites, and space probes. The direct measurements cover the range 10 to 300 Mev and show spectra to be characteristically steep compared with galactic protons. Small differences in the spectral shape and intensity determine whether the solar cosmic rays will be detected at sea level or only at high altitude. Spectra measured on the earth reflect energy sensitive propagation as well as the characteristics of the source. Large differences exist in the time variations of the flare particles. Direct and rapid propagation from the sun is frequently accompanied by a slow decay. Delayed propagation even in the high energy region appears in many events. These delays seem associated with complex propagation routes from the flare region to the earth, frequently because of magnetic plasma clouds in interplanetary space. The lowering of Stormer cutoffs during strong geomagnetic storms is shown by many events studied and occurs coincident with the main phase of storms. Periodic intensity variations of solar cosmic rays have been observed at Minneapolis which may be caused by large-scale oscillations in the main field of the earth. (auth)
- Research Organization:
- Univ. of Minnesota, Minneapolis
- NSA Number:
- NSA-17-012942
- OSTI ID:
- 4755384
- Journal Information:
- J. Phys. Soc. Japan, Journal Name: J. Phys. Soc. Japan Vol. Vol: 17: Suppl. A-II
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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