On Wed, 14 Sep 2011 08:59:16 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

Any strong laser beam will trap dust particles and pull them towards
a direction, I do not remember was it towards the light source or away
from it.
I consider that a thermal effect.

The tweezing is similar to dielectrophoresis and is possibly, but not
probably what you describe. In dielectrophoresis, a normally neutral
molecule (water is such an example) still has an electrical dipole.
The two ends add up to a neutral whole, but in the face of a
non-linear electrical field, the dipole will align along the gradient
and the neutral molecule can be electrostatically steered. It is a
mechanism of fluidic separation done on a scale of what is called "a
laboratory on chip." Panel assays (blood testing for one) are the
goal.

Your 30W narrow beam could present a similar situation.

This, of course, has absolutely NOTHING to do with the claims of
Vorticity.

The Vorticity effect relies on a similar news-flash that arrived here
some months ago about simultaneous reception/transmission on the same
frequency = very critical physical antenna geometries in a
reflectionless environment.

73's
Richard Clark, KB7QHC