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Förslaget inkom 2008-01-16

Whistler waves in the magnetosphere

OBS! ANSÖKNINGSTIDEN FÖR DETTA EXJOBB HAR LÖPT UT.
Whistlers are the dispersed electromagnetic signatures of lightning strikes. The pulse of radiation generated by a lightning discharge propagates a great distance in the Earth-ionosphere waveguide undispersed and with little attenuation. Some portion of this radiation may penetrate through the ionosphere and enter the magnetosphere, where the presence of a plasma results in dispersion. The signal which emerges in the conjugate hemisphere is determined by the properties of the plasma along the path taken through the magnetosphere. The impulsive signal is transformed into a descending tone in the VLF frequency range.

Although whistlers are clearly associated with lightning activity, little is known about the typical region in one hemisphere which acts as a source of whistlers observed around the conjugate point. The objective of this project is to generate a statistical image of the region which is most likely to be the source of whistlers observed in the conjugate hemisphere. This should be done by examing the correlation between the lightning strike and whistler time series, where the former is partitioned into different spatial regions. Two whistler data sets are available: Tihany (Hungary) and Grahamstown (South Africa). Lightning data are acquired from the global WWLLN and VHF systems in Europe and South Africa.

This project is carried out in collaboration with the University of KwaZulu-Natal and the Eötvös University.


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