RE: Research on lasers + high voltage discharges

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >How can a laser which emits photons (a
 >mass less particle... emphasis) direct a flow of plasma?

There are two ways. First off, in an ultraviolet laser beam the photons have
enough energy to knock electrons out of the air molecules (ionizing them)
This is no different to how normal UV light ionizes air. A discharge will
then tend to follow the slightly ionized path.

Secondly, a laser beam is an EM wave just like a radio wave (but MUCH higher
frequency...) Hence, it is made of electric and magnetic fields. If the beam
is powerful enough, the E-field can exceed the dielectric strength of the
air. The air actually turns into glowing plasma along the path of the beam,
and it looks, sounds and smells very like an electric spark (since that's
what it is)

It takes a very powerful laser pulse to do this, though, and it's hard to
make the effect happen over a long beam (as the plasma tends to reflect the
laser light)

Some laser or particle physics guru might correct me on this though. Maybe
the two ways I described are really just "particle" and "wave" explanations
for the same underlying phenomenon?

Steve C.