Heliolatitude distribution of galactic cosmic rays

Journal Article · Thu Aug 01 00:00:00 EDT 1985 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA090iA08p07623· OSTI ID:5375836

Antonucci, E; Attolini, M R; Cecchini, S; Galli, M

An analysis of the annual and semiannual variation of the galactic cosmic ray intensity has been performed for the period 1953-1979 by using the data from the Climax and Dourbes neutron monitors. This analysis, based on a method developed for searching periodicities and recurrences in the cosmic ray intensity, has confirmed the existence of such variations and their phase changes associated with the reversals of the solar magnetic dipole. Hence the importance in the cosmic ray transport of transverse diffusion arising from drift effects due to the curvature and gradient of the interplanetary magnetic field is confirmed, since this is the mechanism which can explain the dependence on the solar magnetic cycle. Such a mechanism is effective when the polarity configuration of the interplanetary magnetic field is well defined and stable. A phase advance of the semiannual variation is observed, which can be explained through the modulation of the heliolatitude distribution of cosmic rays by the activity of the solar magnetic regions migrating in both hemispheres toward the equator, during the 11-year cycle of solar activity. A residual annual variation, detectable when averaging out the effects of the magnetic cycle or when the polarity configuration of the interplanetary magnetic field is not well defined, probably indicates the existence of a preferential azimuthal direction for the access of low-energy galactic cosmic rays into the heliosphere, along the galactic magnetic field.

• Research Organization: Istituto di Fisica dell'Universita, Torino, Italy
• OSTI ID: 5375836
• Journal Information: J. Geophys. Res.; (United States), Vol. 90:A8
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY SPACE
COSMIC RAY PROPAGATION
ANNUAL VARIATIONS
COSMIC RAY FLUX
INTERPLANETARY MAGNETIC FIELDS
PRIMARY COSMIC RADIATION
SOLAR CYCLE
COSMIC RADIATION
IONIZING RADIATIONS
MAGNETIC FIELDS
RADIATION FLUX
RADIATIONS
SPACE
VARIATIONS
640101* - Astrophysics & Cosmology- Cosmic Radiation