Ionospheric redistribution during geomagnetic storms
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- T. J. Immel
- Space Sciences Laboratory University of California Berkeley California USA
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- A. J. Mannucci
- Jet Propulsion Laboratory Pasadena California USA
書誌事項
- 公開日
- 2013-12
- 権利情報
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- http://creativecommons.org/licenses/by-nc-nd/3.0/
- DOI
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- 10.1002/2013ja018919
- 公開者
- American Geophysical Union (AGU)
この論文をさがす
説明
<jats:p>The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle‐latitude region and 30% in the vicinity of the high‐latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced <jats:italic>Dst</jats:italic> index employed to sort the TEC maps into quiet and active (<jats:italic>D</jats:italic><jats:italic>s</jats:italic><jats:italic>t</jats:italic><−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT‐dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large <jats:italic>Dst</jats:italic> variation suggests a possible system‐level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT‐dependent modulation of ion outflow.</jats:p>
収録刊行物
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- Journal of Geophysical Research: Space Physics
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Journal of Geophysical Research: Space Physics 118 (12), 7928-7939, 2013-12
American Geophysical Union (AGU)