Dissemin is shutting down on January 1st, 2025

Published in

American Astronomical Society, Astrophysical Journal, 1(629), p. 556-560, 2005

DOI: 10.1086/431480

Links

Tools

Export citation

Search in Google Scholar

The Influence of Cosmic-Ray Modulation at High Heliospheric Latitudes on the Solar Diurnal Variation Observed at Earth

Journal article published in 2005 by H. Moraal, R. A. Caballero Lopez ORCID, K. G. McCracken, and J. E. Humble ORCID
This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

Full text: Download

Red circle
Preprint: archiving forbidden
Red circle
Postprint: archiving forbidden
Green circle
Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

During the solar minimum period of 1954 the cosmic-ray diurnal variation as observed by neutron monitors and muon telescopes underwent a dramatic swing in its direction of maximum intensity, from the normal value between 16:00 and 18:00 local time to as early as 08:00. It is shown that this swing can be explained as being due to a negative radial density gradient of cosmic rays in the inner heliosphere and that this negative gradient is caused by large radial and latitudinal diffusion mean free paths that bring in particles from high latitudes. In principle, such large diffusion mean free paths should simultaneously cause high intensities, as were observed in 1954.