🚀 go-pugleaf

Could someone set my mind at ease by making a clear statement as to
what is know about sonoluminescence, ultracavitation, and related
topics as opposed to conjecture based on doubtful interpretations of
a very limited data set?

My understanding of cavitation and bubble formation is that it can
involve a very small move away from equilibrium conditions.  All that
is required is that the local pressure in the liquid fall below the
vapour pressure.  I would assume that the bubble fills with vapour
on a time scale close to that required for collapse so I don't
understand why there is any talk about collapse into a "void".

Now as to sonoluminescence, I have the feeling that the conjectures
have run somewhat ahead of the facts in a chain of reasoning that goes
something like the following:  The emission of visible light from
a gas implies high excitation energies such as would result from
temperatures of many tens of kilovolts or higher so we can conclude
the sonoluminescence indicates conditions similar to high-temperature
plasmas are being produced in the bubbles.  It is but one small jump
from there to say that this might be a path to fusion.  It seems to
me, however, that this chain of reasoning has several weak links.
Suppose I suggest as an alternative point of view the notion that
the observed photons are not produced in the volume of the bubble at
all, but are instead coming from the boundary layer of the bubble?
What does the experimental data tell us in that regard?

Why would I think that the light emission is a surface effect?  Basically
because it is something easy to mimmick in the privacy of your own home,
and it can even be done in your kitchen.  Just unroll some plastic wrap
in a dark kitchen.  The layers of plastic film stick together because
the material is a polar dielectric.  When you pull the layers apart the
surfaces are left with unpaired charges in a nonuniform distribution
that is then equilibrated by surface discharges.  When I form a bubble
in a polar dielectric liquid might I not produce the same effect?

I have one more question relating of fractofusion, bubbles, and
non-equilibrium.  Suppose by hook or crook I do produce a transient
electric field in the presence of some deuterons and some electrons.
What keeps the electrons sitting still while the deuterons accelerate
to velocities high enough to induce fusion?  I have always be taught
that a mass ratio of roughly 4000:1 would leave the deuterons sitting
still while the electrons rushed off to cancel the field.  Of course
that is old fashioned theory.

Dick Blue
NSCL @ MSU