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(meteorobs) Electrophonic meteors
Dear fellow meteor observers
I would like to draw your attention to a recent article from our group,
entitled: "Instrumental recording of electrophonic sounds from Leonid
fireballs", by G. Zgrablic et al. The article considers the phenomenon
of the electrophonic meteors and it will appear in the Journal of
Geophysical Research.
The electrophonic sounds, which are heard simultaneously with an
appearance of a bright meteor, are a longstanding astronomic mystery.
This is the contra-intuitive phenomenon: normal sounds from a meteor
should be heard couple of minutes after the meteor, similarly as thunder
lags behind distant lighting. A full evaluation of the electrophonic
phenomenon was undermined by the lack of instrumental recordings - only
witness reports existed.
In the article, we present the first instrumental recording of the
electrophonic sounds detected during the 1998 Leonid meteor storm over
Mongolia. We demonstrate that the physical characteristics of
electrophones from Leonid meteors cannot be explained satisfactory in
the framework of the existing theories. In addition, it is suggested
that the coupling of meteors to atmospheric charge dynamics and
ionosphere is much stronger than previously expected. This can have more
general implications, beyond the electrophonic phenomenon.
Preprint of the article and additional information, pictures and videos
can be accessed at the project's web page:
http://fizika.org/ilwcro/results/
More importantly, I would like to remind you about the project "Global
Electrophonic Fireball Survey", coordinated by D. Vinkovic from Univ. of
Kentucky (e-mail: dejan@ccsdot ukydot edu). The aim of the project is to
collect witness reports of the electrophonic sounds. If you experienced
electrophonic phenomena, please fill up the on-line form and make an
important contribution to the understanding of this effect. Web address:
http://gefs.ccsdot ukydot edu/
Greetings,
Slaven Garaj
Institute of Nuclear Engineering (IGA)
Department of Physics
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne
Tel.: +41 (21) 693 4337
Fax: +41 (21) 693 4461
e-mail: slaven.garaj@epfl.ch
homepage: http://nanotubes.epfl.ch/garaj/
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