Pre-storm electron density enhancements at middle latitudes
Substantial increases of the F2 region peak electron density several hours to a day before the geomagnetic storm onset, the so-called pre-storm enhancements, belong to still not clear and hardly predictable features of the ionospheric disturbances. This paper presents analysis of the pre-storm enhan...
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Published in | Journal of atmospheric and solar-terrestrial physics Vol. 70; no. 15; pp. 1848 - 1855 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.12.2008
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Subjects | |
Online Access | Get full text |
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Summary: | Substantial increases of the F2 region peak electron density several hours to a day before the geomagnetic storm onset, the so-called pre-storm enhancements, belong to still not clear and hardly predictable features of the ionospheric disturbances. This paper presents analysis of the pre-storm enhancements observed at middle latitudes for 15 storms out of 65 strong-to-severe geomagnetic storms of the period 1995–2005. All 15 events were accompanied by significant (>20%) increases of foF2 before the storm onset over European area. We focus on the longitudinal extent and height profile of the pre-storm enhancements, particularly on their effects on the F1 and E regions of the ionosphere. Possible origin of such enhancements is also partly discussed. We observe no systematic effect of pre-storm enhancements of foF2 in electron density profiles in the F1 region. The E region (foE) appears to be insensitive to pre-storm enhancements. We find the pre-storm enhancements to be confined to the F2 region. The longitudinal extent of the pre-storm enhancements seems to be 120–240° based on comparison of simultaneous foF2 measurements in Europe, northern USA, and Eastern Asia. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1364-6826 1879-1824 |
DOI: | 10.1016/j.jastp.2008.01.014 |