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| Titel |
Changes in cosmic ray cut-off rigidities due to secular variations of the geomagnetic field |
| VerfasserIn |
A. Bhattacharyya, B. Mitra |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 15, no. 6 ; Nr. 15, no. 6, S.734-739 |
| Datensatznummer |
250012833
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| Publikation (Nr.) |
 copernicus.org/angeo-15-734-1997.pdf |
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| Zusammenfassung |
| An analytical expression is derived for the
cutoff rigidity of cosmic rays arriving at a point in an arbitrary direction,
when the main geomagnetic field is approximated by that of an eccentric dipole.
This expression is used to determine changes in geomagnetic cutoffs due to
secular variation of the geomagnetic field since 1835. Effects of westward drift
of the quadrupole field and decrease in the effective dipole moment are seen in
the isorigidity contours. On account of the immense computer time required to
determine the cutoff rigidities more accurately using the particle trajectory
tracing technique, the present formulation may be useful in estimating the
transmission factor of the geomagnetic field in cosmic ray studies, modulation
of cosmogenic isotope production by geomagnetic secular variation, and the
contribution of geomagnetic field variation to long term changes in climate
through cosmic ray related modulation of the current flow in the global electric
circuit. |
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