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(meteorobs) Re: eta aquarids (or solar max effects on meteors)





Marco>>Interresting to read about the lean eta Aquarid rates. Perhaps, part of
the phenomenon is caused by the current solar activity. Solar activity 
influences the upper atmosphere, and that in turn influneces visibility 
of meteors. With higher solar activity influence, meteor rates become 
lower, especially for fast meteor streams. But the difference should be 
not more than 20% of peak activity. Anyway, very interresting.<<

Also on an earlier post by Tom Ashcraft>>Also as I understand it the outer
edge of the ionosphere at solar minimum
>is about 80 kms out but during solar maximum the outer edge is 140 kms or
>so out. 
>Wouldn't this sky expansion mean that more meteors are intercepted or is
>this all negligible?<<

In a past post about this topic from Rainer Arlt, his reply was as follows:

Rainer>>Ionosphere means the part of the atmopshere where the abundance of
free
electrons causes some conductivity. The range where the electron density is
large can vary strongly with solar activity. For meteors I think the main
parameter is the air density which the particle with cosmic velocity faces
when
entering the atmosphere. This density varies much less distinctly than the
free-electron density. The free-electron density is between 10^10 to 10^11
electrons per cubic meter. The molecular density, however,  is about 10^19
molecules per cubic meter, i.e. at least 
100 million times higher. So the meteoroid will not see any difference between
high or low ionosphere when entering the atmosphere. The only thing that could
be affected is the ionisation and recombination of air molecules, i.e. the
luminous process of the meteor. I guess we may expect brightness variations
with
different free-electron densities, but also guess they are extremely small.
Ionosphere expansion does not mean the atmosphere expands -- the range where
free electrons can be found varies.<<

Rainer's posting seems to counter Marco's and I am inclined to agree with
Rainer. I believe I came across a previous post also on this topic by Lunsford
that stated that some studies have indicated that perhaps there are more
sporadic meteor activity during a solar minimum? I don't know how reliable
these studies would be or who did them, but this also seems to counter what
Marco says. I'm not sure how any affect could occur to meteors either during a
solar max or minimum based upon what Rainer has stated?
George Zay