Accession Number:

ADA043996

Title:

The Effects of Recent Secular Variations of the Geomagnetic Field on Vertical Cutoff Rigidity Calculations,

Descriptive Note:

Corporate Author:

AIR FORCE GEOPHYSICS LAB HANSCOM AFB MASS

Personal Author(s):

Report Date:

1977-09-02

Pagination or Media Count:

7.0

Abstract:

Recent geomagnetic measurements have shown that changes in the geomagnetic field have deviated from the predictions of the original International Geomagnetic Reference Field IGRF coefficients and associated time derivatives. Accordingly, a new set of time derivatives has been determined with the suggestion that these be applied for time periods after 1975. To ascertain the effects of the changes of geomagnetic field time derivatives on cosmic ray analyses, vertical cutoff rigidities were calculated for selected locations using the IGRF 1965 field coefficients and associated time derivatives and the IGRF 1975 field coefficients and the new time derivatives making each set of calculations appropriate for a 1980 Epoch. A comparison of these two sets of calculations shows that the uncertainty in predicted magnetic fields does not appear to be a serious limiting factor in the use of calculated vertical cutoff rigidities for the analyses of cosmic radiation data. Author

Subject Categories:

  • Atmospheric Physics
  • Geomagnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE