Thread: Speed of waves
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Old March 30th 11, 08:36 AM posted to rec.radio.amateur.antenna
Szczepan Bialek Szczepan Bialek is offline
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Default Speed of waves


"Jim Lux" napisal w wiadomosci
...
Szczepan Bialek wrote:

Speed of waves in a dispersive medium is temperature dependent.


Maybe.. depends on the medium, I should think, and the mechanism of the
dispersion. Some dispersion might be due to ionization (which may or may
not be temperature dependent).


It is known that the speed of light in air is temperature dependent ( mirage
and E. Schmidt's method in Fluid dynamics).
in vacuum also. But I culd find the results.

In the Solar System the temperatures are decreasing with the distance
from the Sun.


Temperature in a vacuum and with ionized particles is tricky to define.
It has to do with mean free path and the velocity of the particles. When
the number density gets down in the "few atoms per cubic meter" and the
mean free path gets to be meters or km, I think you need to start thinking
in different ways.


May be, but at first I must know if the mirage works in vacuum.

One common confusion is an assumption of a particular velocity
distribution in charged particles and then using the 11000K = 1 eV
relation.


Yes. But the simple measurement of the mirage or E. Schmidt's effect in
vacuum will clarify everything.
"I am sure that such experiments were done". Could you help?
S*