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| Titel |
Modeling of ionospheric electromagnetic earthquake precursors |
| VerfasserIn |
Claudia-Veronika Meister, Benjamin Mayer, Dieter H. H. Hoffmann |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056469
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| Zusammenfassung |
| The many-fluid magnetohydrodynamic theory is applied to describe modifications and the
additional excitation of electromagnetic waves in the ionospheric E-layer by acoustic waves
originating from lower altitudes. In comparison with former works here both the stratification
of the ionosphere and the background electromagnetic field are taken into account. The
altitudinal profiles of the plasma parameters and the electromagnetic field at times without
acoustic waves are fitted to recent experimental data. It is shown that in the E-layer usual
magnetohydrodynamic waves, as Alfvén and magnetoacoustic ones, are generated.
However, by the influence of the acoustic waves and the related modification of the
momentum transport between the neutral and charged particles, the amplitudes
and propagation directions of the magnetohydrodynamic waves are changed. In
the work mathematical expressions for the plasma density and electromagnetic
field variations are derived and applied to the case of the appearance of acoustic
waves with periods between 20 s and 5 min, which might occur before earthquakes.
Besides related temperature fluctuations in the E-layer are evaluated. The results
of the model are compared with recently observed changes of characteristic foE-
and foEs-frequencies of the ionosphere one-three days before Asian earthquakes. |
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