The solar modulation of galactic cosmic rays in the outer heliosphere

Abstract

view Abstract Citations (117) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The solar modulation of galactic cosmic rays in the outer heliosphere McDonald, F. B. ; Trainor, J. H. ; Lal, N. ; Van Hollebeke, M. A. I. ; Webber, W. R. Abstract The intensity changes of galactic cosmic rays associated with the enhanced solar activity during the onset of cycle 21 were observed by Pioneer 10 and Helios 1 and 2, over an extended range of energy and heliocentric distance that provides new insight into the relative importance of the various processes involved in the long-term modulation. A close correspondence is found between changes at 1 AU and those at 23 AU, for hydrogen and helium in the range of 100-200 MeV per nucleon. The time delay observed corresponds to an outward propagation velocity of some 550 km/sec, suggesting that the recently discovered, moderately long-lived, radially propagating shock waves in the outer heliosphere may play a key role in the long-term modulation. Publication: The Astrophysical Journal Pub Date: October 1981 DOI: 10.1086/183661 Bibcode: 1981ApJ...249L..71M Keywords: Cosmic Rays; Galactic Radiation; Heliosphere; Interplanetary Medium; Solar Activity Effects; Energy Spectra; Helios 1; Helios 2; Helium; Modulation; Pioneer 10 Space Probe; Shock Wave Propagation; Spaceborne Astronomy; Space Radiation full text sources ADS |