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Title: Recovery phase of galactic cosmic ray modulation in the outer heliosphere

Journal Article · · Geophys. Res. Lett.; (United States)

Energetic hydrogen and helium nuclei from the galaxy (cosmic rays) enter the solar system with varying degrees of difficulty during the 11-year solar magnetic cycle, resulting in spatial and temporal variations of particle intensities in the heliosphere. We report observations of these variations from the ISEE-3, Voyager 1 and 2, and Pioneer 10 spacecraft during the period from early 1981 to early 1986 and for heliocentric distances ranging from 1 to 37 AU. During this time the high energy intensities in the outer heliosphere have been increasing exponentially at a rate of approximately 20%/year with occasional interruptions due to enhanced solar activity. There are long delays (--3 years) in the recovery of the intensity of low energy particles relative to high energy particles that significantly alter the energy spectra. The radial intensity gradients measured in the ecliptic plane are observed to remain constant or to decrease at the time of the reversal of the solar magnetic poles in 1980.

Research Organization:
NASA Headquarters
OSTI ID:
5111463
Journal Information:
Geophys. Res. Lett.; (United States), Vol. 13:8
Country of Publication:
United States
Language:
English