Titre du document

Cerenkov scintillation ounter measurements of the intensity and modulation of low rigidity cosmic rays and features of the geomagnetic cutoff rigidity

Lien vers le document
Nom du Corpus

AstroConcepts

Auteur(s)
  • W. R. Webber
  • F. B. McDonald
Résumé

The primary cosmic radiation has been measured with a Cerenkov scintillation counter at various times in the solar cycle at locations having nominal cutoff rigidities of 0.8, 1.6, and 2.7 bv. Results are used here to delineate spectral features of low rigidity protons and ? particles and to examine the rigidity and charge dependence of the eleven?year solar modulation. Details of particle transmission near the geomagnetic cutoff are also examined. The measurements indicate: (1) The observed nonsharp cutoff appears to be primarily due to expected transmission effects in a dipole?like field and to instrumental effects, and the actual cutoff is quasi?sharp in the Störmer sense. This is true even though the observed cutoff may be reduced to half that to be expected from the internal field, presumably because of external current systems flowing in the magnetosphere and its boundary. (2) The rigidity dependence of the eleven?year modulation of protons and that of ? particles are closely similar above ?1.2 bv. None of the presently proposed models for this modulation agree with our results. The implications of this lack of agreement are discussed, and it is concluded that certain general features of particle motion in the interplanetary medium not considered in present models may be of importance. One such general feature may be diffusive deceleration in the radially expanding interplanetary medium, which is shown to have the same effect as a static heliocentric electric field. (3) The differential spectrum of galactic cosmic rays near sunspot minimum at about 1?bv rigidity is either flat or falling slightly toward lower rigidities. The measurements in the rigidity range below 1 bv are compared with recent observations in this range.

Langue(s) du document
Anglais
Année de publication
1964
Revue

Journal of Geophysical Research

Éditeur
Wiley
Type de publication
journal
Type de document
article
Présence de XML structuré
Non
Version de PDF
1.2
Score de qualité du texte
10
Nom du concept
  • Landau fluctuations
Catégories Science-Metrix
  • 1 - natural sciences ; 2 - earth & environmental sciences ; 3 - meteorology & atmospheric sciences
Catégories Scopus
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Palaeontology
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Earth and Planetary Sciences (miscellaneous)
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Atmospheric Science
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Earth-Surface Processes
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Geochemistry and Petrology
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Soil Science
  • 1 - Physical Sciences ; 2 - Environmental Science ; 3 - Water Science and Technology
  • 1 - Physical Sciences ; 2 - Environmental Science ; 3 - Ecology
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Aquatic Science
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Forestry
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Oceanography
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Geophysics
Catégories WoS
  • 1 - science ; 2 - geosciences, multidisciplinary
Identifiant ISTEX
94FCFC790F3B68A6B1B4ED09C146DD9AA3C7E939
ark:/67375/WNG-2Z848PNP-S
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