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November 2002: The first review of almost 100 witness reportes collected
Vinkovic, D., Garaj, S., Lim, P. L., Kovacic, D., Zgrablic, G., Andreic, Z.
" Global Electrophonic Fireball Survey: a review of witness reports - I.
", WGN, the Journal of the IMO, Vol.30, December 2002, pp.244-257
Despite more than 300 years since its first scientific description, the phenomenon of
electrophonic sounds from meteors is still eluding complete physical explanation.
According to the accepted knowledge, the sound itself is created by strong electric
fields on the ground induced by the meteor. Nonetheless, there is no convincing theory
that can fully explain how a meteor can generate such a strong electric field. Extreme
rareness of the phenomenon has prevented a substantial experimental work so far; thus,
consequently, it remains on the margins of scientific interest. This is quite
unfortunate since these electric fields suggest existence of a highly complex
electromagnetic coupling and charge dynamics between the meteors and the ionosphere.
Therefore, the existing theoretical work relies mostly on the witness reports. The
Global Electrophonic Fireball Survey (GEFS) is the first systematic survey of witness
reports of these sounds with a standardized questionnaire designed exclusively for this
phenomenon. Here we present the overall picture of the phenomenon that emerged after
almost 100 reports collected by GEFS. It becomes clear now that the lover meteor
brightness limit is about -2m, suggesting a bias in the existing electrophonic sounds
catalogues toward brighter meteors. In contrast to the current belief that such low
brightness electrophonic meteors produce transient sounds, we find that they can also
produce sustained sounds. The current theories can not accommodate these results. We
revive the old idea that the electrophonic sounds can be created by the corona
discharge mechanism, in addition to the existing prevalent suggestion of resonant
vibration of objects on the ground.
(or at arXiv.org: arxiv.org/abs/astro-ph/0211203)
ALL REPORTS AVAILABLE HERE: GEFS_all_reports.tar.gz
The first instrumental recording of electrophonic sounds recorded during
the 1998 Leonids in Mongolia. The analysis yielded interesting results and
showed that the current theories cannot explain them.
Zgrablic, G., Vinkovic, D., Gradecak, S., Kovacic, D., Biliskov, N., Grbac, N.,
Andreic, Z., Garaj, S.,
"Instrumental recording of electrophonic sounds from Leonid fireballs"
Journal of Geophysical Research - Space Phys. 107(A7),
- read more about it: here
The GEFS Submission Form
published in WGN
Vinkovic, D., Andreic, Z., Garaj, S., Kovacic, D., Mladinov, M., Zgrablic, G.,
"Global Electrophonic Fireball Survey"
WGN, the journal of the IMO, 28, 48-53 (2000)
- download: gziped PostScript