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| Titel |
The linear dependence of GHz scintillation on electron density observed in the equatorial anomaly |
| VerfasserIn |
J. A. Whalen |
| 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. 4 ; Nr. 27, no. 4 (2009-04-09), S.1755-1761 |
| Datensatznummer |
250016497
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1755-2009.pdf |
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| Zusammenfassung |
| The dependence of scintillation caused by equatorial bubbles on the electron
density in the post sunset anomaly cannot generally be determined because
the irregularities that produce the scintillation obscure the measurement of
the electron density. This work addresses this problem with the introduction
of a new technique based on the finding that anomaly electron density is so
regular that its LT distribution can be fit by a polynomial over its
post-sunset extent. By means of this polynomial, gaps in the data caused by
the irregularities can be inferred where otherwise not measurable.
Observations are of amplitude scintillation at 1.5 GHz from the Marisat
satellite and of NmF2 measured by ionospheric soundings at Ascension I. in
Mar 2001 during solar maximum. The result is that the well defined maximum
of the S4 scintillation index is a linear function of coinciding NmF2.
Evidence that supports this result has been found in 3 differing cases: The
first finds that both S4 and NmF2 decrease linearly with LT; the second,
that both occurrence of scintillation and NmF2 increase linearly with F10.7
cm solar flux; the third finds a linear relation between occurrence of
scintillation at 137 MHz and NmF2. The importance of these results is that
scintillation is caused by the bubble, but its magnitude is determined by
the magnitude of the electron density that the bubble intersects. A further
implication is that, given the unpredictability of bubbles, if NmF2 could be
predicted, the maximum level of S4 possible could be predicted if a bubble
were to occur. |
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