From: garcia22@llnl.gov (Manuel Garcia)
Newsgroups: sci.physics.plasma
Subject: Re: Acoustic Wave
Followup-To: sci.physics.plasma
Date: Thu, 26 Mar 1998 14:52:22 +0800
Organization: Lawrence Livermore National Laboratory
Message-ID: <garcia22-260398145223@macgarciam.llnl.gov>
References: <6f169e$nsd$1@usenet56.supernews.com>


In article <6f169e$nsd$1@usenet56.supernews.com>, "Bruno Shubert"
<bshubert@redshift.com> wrote:

>
> Many years ago while I was at the Czech Technical University in Prague I
> conducted an experiment involving propagation of acoustic waves in low
> temperature plasma. It was observed that when a low frequency (168Hz)
> acousic wave propagated in a gas discharge and the pertubation current was
> displayed versus the DC current it exibited peaks corresponding to gas
> mixtures (such as air) while no peaks were observed in pure gas. This was
> part of my disertation. Due to the events in 1968 I had to interrupt this
> research and leave that country. I have not had an opportunity to continue
> this investigation ever since. Yet, I would be wery interested to learn if
> any research has been done in this or similar area. If anybody has any
> information or interest I would very much appreciate hearing from you.
>
> Sylvia Shubert

An electric discharge through a molecular gas mixture can initiate a
chemical process in which numerous new species are formed. This change in
the medium could have an influence on acoustic wave propagation as well as
overall impedance (or conductivity). People have asked about "plasma tube
acoustic amplifiers" in this newsgroup. One niche interest is in tube
amplifiers for electric guitars (the search for a better Fender Twin Reverb
Amp); I have heard of a company specializing in these "vacuum tubes." The
following references may help begin a search.

1a) A. W. Trivelpiece, "Slow-Wave Propagation in Plasma Waveguides," San
Francisco Press, Inc., 255 12th Street, San Francisco CA, 1967 (Library of
Congress # 67-20699).

1b) A. W. Trivelpiece, R. W. Gould, "Space charge waves in cylindrical
plasma columns," Journal of Applied Physics, Vol. 30, No. 11, 1784-1793,
November 1959.

2) A. von Engel, "Electric Plasma: Their Nature and Uses," International
Publications Service Taylor & Francis Inc., New York, 1983. (acoustic
effects mentioned in chapter 6), ISBN 0-8002-3076-0

3) M. F. Hamilton, D. T. Blackstock, "Nonlinear Acoutics," Academic Press,
San Diego CA, 1998, ISBN 0-12-321860-8. [I didn't see any refernce to
ionized media, however this review of acoutics might have references that
lead in your direction]

4) L. D. Landau, M. D. Lifshitz, "Fluid Mechanics," Chapter 8 "Sound,"
Pergammon Press/Addison-Wesley Publishing Company, Reading MA, 1959. The
propagation of sound in dissipative, dissociating, and ionized media has
interested many fluid dynamicists besides Landau.

You might just have to finish your thesis to fill in a gap of scientific
knowledge.
--
Manuel Garcia
LLNL L-153
POB 808, Livermore, CA 94550
(925) 422-6017
garcia22@llnl.gov