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| Titel |
Height-resolved energy exchange rates in the ionosphere |
| VerfasserIn |
L. Cai, A. Aikio, T. Nygrén, R. Kuula |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066586
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| Zusammenfassung |
| The electromagnetic energy exchange between the high-latitude ionosphere and
magnetosphere can be described in terms of electromagnetic energy exchange rate qEM,
which is a sum of ion-neutral frictional heating rate qJ (sometimes called Joule
heating) and work done on neutrals qm. We have examined the height-resolved
energy exchange rates in the ionosphere by using a one-month database obtained by
EISCAT incoherent scatter radar measurements in Tromso. The CP2 scan mode of
the EISCAT radar makes it possible to deduce conductivities, electric fields and
neutral winds in the E region and hence estimate the different energy exchange
rates.
We will show characteristic examples for different situations, like a quiet ionosphere
dominated by altitude-dependent neutral wind structures (probably caused by atmospheric
gravity waves), or active conditions dominated by strong electric fields and intense
electromagnetic energy input into the ionosphere. In general, the ion-neutral frictional heating
altitude profiles are affected by vertical structuring in horizontal winds. Also, the ionosphere
can be at some altitudes a sink of EM energy and at other altitudes a source of EM energy. On
rare occasions, the net effect of the ionosphere is to act as an EM dynamo (source of energy). |
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