Re: differences between sound and light waves?

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2 total messages Started by J. Eric Grove Tue, 23 Feb 1988 17:41

#728

Author: J. Eric Grove
Date: Tue, 23 Feb 1988 17:41

18 lines
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In article <3129@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes:
>The blue glow is the result of massive (i.e., not massless)
>particles losing energy as they slow to the speed of light in water.
>
>
>  --John Carr   (jfc@ATHENA.MIT.EDU)

Note that this statement is misleading.  Charged particles lose about 3 orders
of magnitude more energy in ionizing the medium they are traversing than in
generating Cerenkov radiation.  Typical ionization energy losses for
relativistic particles are ~2*Z*Z MeVcm2/g, while typical energy losses to
Cerenkov radiation are ~Z*Z keVcm2/g.  Mr. C's radiation is only a minor
player in energy loss.

		J. Eric Grove
		jeric@tybalt.caltech.edu
		...rutgers!cit-vax!tybalt.caltech.edu!jeric

Re: differences between sound and light waves?

#730

Author: Carl Witthoft
Date: Wed, 24 Feb 1988 20:36

21 lines
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In article <5537@cit-vax.Caltech.Edu> jeric@tybalt.caltech.edu.UUCP (J. Eric Grove) writes:
>In article <3129@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes:
>>The blue glow is the result of massive (i.e., not massless)
>>particles losing energy as they slow to the speed of light in water.
>Note that this statement is misleading.  Charged particles lose about 3 orders
>of magnitude more energy in ionizing the medium they are traversing than in
>generating Cerenkov radiation.  Typical ionization energy losses for
>		J. Eric Grove
What's going on here? I thought that the whole point of
Cerenkov radiation was that it is a "bow wave" of light given off
by a particle moving faster than the speed of photons in the present
medium.  The radiation is somewhat like a sonic boom.


-- 

Alix's Dad ( Carl Witthoft @ Adaptive Optics Associates)
{ima,harvard}!bbn!aoa!carl
54 CambridgePark Drive, Cambridge,MA 02140 617-864-0201
"People unclear on the concept: 'Nah, I don't want to windsurf,
I wanna do more C-programming.' "

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