Rick Monteverde writes:
I suspect that the acoustic output is ordinary and isn't any
more beam-like than any sound at that frequency.
There is ongoing R&D of coherent acoustic phonon generation in
piezoelectric semiconductors
http://arxiv.org/abs/cond-mat/0301031
and optical phonon pumping
http://flux.aps.org/meetings/BAPSMAR95/abs/SR1803.html
which muddies the difference between light and sound in the
infrared and terahertz ranges. There is a definite overlap in the
terahertz range which has applicability to LENR. This is not
visible light but is arguably "light" in that it can be both
photonic and phononic. I guess that is what Richard was refering
to.
...and, yes, the same kind of beam-like effect might be possible
with phonons- but only in specialized homogenous materials - as
air likely would scatter waves too much. Unlike photons, which do
not "need" air to propagate, phonons need mass in order to
propagate... hey... isn't that why the idea of "aether" originated
in the first place?
(legends of acoustic stone levitation not withstanding)
... there may be a grain of truth in many legends, but that one
demands a high degree of supension of disbelief.
It might be called an AASER - acoustic amplification (by)
stimulated emission (of phonon) radiation. Needs a better
acronym though.
One term now in use is "Saser". This paper calls it a "phaser" but
Star Trek got there first on that one:
http://arxiv.org/abs/cond-mat/0402640
Jones
BTW I posted earlier some ideas on a related issue (LENR) before.
Esp in re: the "Letts/Cravens experiment" (which used a laser).
The gist of that is a "triple coherency" overlapping range may
have special synergy for LENR.
The "triple" levels of wave overlap envisions terahertz level
waves of:
1) light (photon)
2) sound or heat (phonon)
3) EM (magnetic but not photonic as in a pulsing magnetic field)
Actually the last one is a bit confusing - but envisions a static
magnetic field which does not change in bulk properties - but
which is virtually "pulsed" at the nano-level by 1) and 2)
interacting with 3).
