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| Titel |
A potential lag between the open solar magnetic source flux and solar EUV and X-ray emissions as measured by the Earth's ionosphere during total solar eclipses |
| VerfasserIn |
C. J. Davis, S. A. Bell, R. Stamper, A. W. V. Poole, L. A. McKinnell, P. Wilkinson |
| 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 ; 27, no. 6 ; Nr. 27, no. 6 (2009-06-18), S.2449-2456 |
| Datensatznummer |
250016558
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2449-2009.pdf |
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| Zusammenfassung |
| Measurements of the ionospheric E-region during total solar eclipses have
been used to provide information about the evolution of the solar magnetic
field and EUV and X-ray emissions from the solar corona and chromosphere. By
measuring levels of ionisation during an eclipse and comparing these
measurements with an estimate of the unperturbed ionisation levels (such as
those made during a control day, where available) it is possible to estimate
the percentage of ionising radiation being emitted by the solar corona and
chromosphere. Previously unpublished data from the two eclipses presented
here are particularly valuable as they provide information that supplements
the data published to date. The eclipse of 23 October 1976 over Australia
provides information in a data gap that would otherwise have spanned the
years 1966 to 1991. The eclipse of 4 December 2002 over Southern Africa is
important as it extends the published sequence of measurements. Comparing
measurements from eclipses between 1932 and 2002 with the solar magnetic
source flux reveals that changes in the solar EUV and X-ray flux lag the
open source flux measurements by approximately 1.5 years. We suggest that
this unexpected result comes about from changes to the relative size of the
limb corona between eclipses, with the lag representing the time taken to
populate the coronal field with plasma hot enough to emit the EUV and X-rays
ionising our atmosphere. |
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