[Aavso-sid-list] Meteor Storms and Possible VLF Effects ?

[Rodney Howe]

It seems most of the SID work at VLF frequencies is done at integration 
times of minutes or at most 1 second intervals.  Would it be easier to 
detect meteors with an ELF receiver?  Would you need to capture meteor 
emissions with sound cards or high data capture rates?

Here's an ELF radio which might work:
http://home.flash.net/~evogel/natrad2.pdf

Also, will it be difficult to discriminate Sprites from meteors?  A lot of 
work has been done on Sprites at both ELF and VLF
http://elf.gi.alaska.edu/spr20010406.html
http://www.sgo.fi/~fredrik/publications/SpritesSearch.html

Rodney


Here's more ELF and VLF work.
http://elf.gi.alaska.edu/fagu98.html


----- Original Message ----- 
From: "Thomas Ashcraft" <ashcraft at heliotown.com>
To: <aavso-sid-list at aavso.org>
Sent: Sunday, February 17, 2008 11:04 AM
Subject: Re: [Aavso-sid-list] Meteor Storms and Possible VLF Effects ?


For those interested in this article for their own personal research I
can email it as a .pdf file. But it cannot be posted on the web publicly
due to copyright concerns. For personal research only please.

You can email me at    :  ashcraft(at)heliotown.com

Thomas Ashcraft wrote:
> Have any SID observers here connected any observations to meteor storms?
>
> For those interested in the possible connection between meteors and VLF
> effects: Here is the abstract of a paper published in Science. Sorry, I
> don't know how to retrieve the full paper. I do remember reading this
> article many years ago and questioning the results that the researchers
> arrived at.
>
> - Thomas Ashcraft
>
> *********
>
> http://www.sciencemag.org/cgi/content/abstract/246/4931/787?ck=nck
>
> /Science/ 10 November 1989:
> Vol. 246. no. 4931, pp. 787 - 790
> DOI: 10.1126/science.246.4931.787
>
>
> Articles
>
>
> Effects of the Large June 1975 Meteoroid Storm on Earth's Ionosphere
>
> *P. Kaufmann ^1 , V. L. R. Kuntz ^1 , N. M. Paes Leme ^1 , L. R. Piazza
> ^1 , J. W. S. Vilas Boas ^1 , K. Brecher ^2 , and J. Crouchley ^3 *
>
> ^1 Centro de Ráadio-Astronomia e Aplicacäes Espaciais-CRAAE, Escola
> Politécnica, Universidade de São Paulo, C. P. 8174, 05508—São Paulo, 
> Brazil
> ^2 Department of Astronomy, Boston University, Boston, MA 02215
> ^3 Department of Physics, University of Queensland, St. Lucia,
> Queensland 4067, Australia
>
> The June 1975 meteoroid storm detected on the moon by the Apollo^
> seismometers was the largest ever observed. Reexamination of^ radio data
> taken at that time showed that the storm also produced^ pronounced
> disturbances on Earth, which were recorded as unique^ phase anomalies on
> very low frequency (VLF) radio propagation^ paths in the low terrestrial
> ionosphere. Persistent effects^ were observed for the major storm period
> (20 to 30 June 1975),^ including reductions in the diurnal phase
> variation, advances^ in the nighttime and daytime phase levels, and
> reductions in^ the sunset phase delay rate. Large nighttime phase
> advances,^ lasting a few hours, were detected on some days at all VLF
> transmissions,^ and for the shorter propagation path they were
> comparable to^ solar Lyman alpha daytime ionization. Ion production
> rates attributable^ to the meteor storm were estimated to be about 0.6
> to 3.0 ions^ per centimeter cubed per second at the E and D regions,
> respectively.^ The storm was a sporadic one with a radiant (that is, the
> point^ of apparent origin in the sky) located in the Southern
> Hemisphere,^ with a right ascension 1 to 2 hours larger than the sun's
> right^ ascension.
>
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>

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