Solar modulation of galactic cosmic rays near solar minimum (1965)
- 15 May 1968
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Physics
- Vol. 46 (10), S887-S891
- https://doi.org/10.1139/p68-375
Abstract
The results of the continuous monitoring of the intensity of cosmic rays (of energy > 50 MeV) with identical G-M counter telescopes flown in satellites IMP I, II, and III and OGO-I are presented along with the differential spectrum studies obtained from balloon flights at Fort Churchill and from satellites. A comparison of the time behavior of the G-M counter data with Deep River neutron monitor data suggests the presence of a "hysteresis" type of behavior due to spectral changes occurring near solar minimum. The existence of this "hysteresis" suggests that the radial gradient of cosmic rays near the earth could be much smaller than the ~ 10%/AU obtained by O'Gallagher and Simpson (1967) and O'Gallagher (1967) at higher energies. The long-term intensity variation of cosmic rays seems to follow the Ap index rather closely in phase, in contrast to sunspot numbers which display a pronounced phase difference with cosmic-ray intensity. The differential spectra of protons and He nuclei have been analyzed in terms of two different models for the propagation in the interplanetary medium. The modulations indicated by the present data seem to disagree with a diffusion coefficient proportional to βR where β and R are the velocity and rigidity of the particle respectively (Jokipii 1966).Keywords
This publication has 5 references indexed in Scilit:
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- Low-Energy Cosmic-Ray Modulation Related to Observed Interplanetary Magnetic Field IrregularitiesPhysical Review Letters, 1966
- The multiply charged primary cosmic radiation at solar minimum, 1965Journal of Geophysical Research, 1966
- Results from the Imp 1 GM counter telescope experimentJournal of Geophysical Research, 1965
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