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| Titel |
Area of whistler penetration to the ionosphere |
| VerfasserIn |
Jiri Fiser, Jaroslav Chum, Gerhard Diendorfer, Michel Parrot, Ondrej Santolik |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035114
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| Zusammenfassung |
| We present results of a study related to the penetration of electron whistlers induced by
lightning to the ionosphere. Using automatic method, we identify the fractional hop whistlers
in the VLF spectrograms computed from the data recorded with the ICE experiment
onboard the DEMETER satellite. We get the information about times at which the
whistlers were recorded and also estimate their average amplitudes. We compare
the identified whistlers with lightning detected by the EUCLID detection network
and, using statistical aproach, we find the pairs causative lightning-whistler. For
each pair we can find the dependence of the whistler amplitude on the distance
between the lightning and pretended wave penetration point to the ionosphere and also
on the lightning current. Superposing data from large number of such pairs, we
obtain information about the area over which the whistler waves penetrate to the
ionosphere.
In our analysis, we processed data from 186 DEMETER passes over the European region
and found ~ 30,000 of pairs causative lightning-whistler. We find that mean whistler
amplitude monotonically decreases with horizontal distance up to ~1000Â km from the
lightning source. At larger distances, the mean whistler amplitude usually merges into
the background noise and the whistlers become undetectable. The maximum of
whistler intensities is shifted from the satellite magnetic footprint ~ 1° owing to the
oblique propagation. The average amplitude of whistlers increases with the lightning
current. At nighttime (late evening), the average amplitude of whistlers is about
three times higher than during the daytime (late morning) for the same lightning
current. |
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