[net.physics] IFEL Accelerators

evans@mhuxt.UUCP (07/14/83)

To describe an inverse free electron laser let me first  (loosely) describe
a free electron laser....

A free electron laser consists of a high energy free electron that is
scattered by a spatially varying magnetic field. The upper laser state
consists of a fast electron and a virtual photon from a rippled magnetic
field. The lower state is a lower energy electron and a scattered photon.
With many scattering events the scattered radiation builds up to a point
where it stimulates further scattering -- we have a laser.

In an inverse free electron laser you couple a charged particle to the
radiation of an intense laser beam by perturbing the particle's trajectory
so there is an oscillating transverse component in phase with the
radiation. The scheme is to somehow focus the beam of a BIG laser over
a long distance and shoot it , along with a beam of charged particles
across wiggler magnets(similar to the wiggler magnets that are placed
in electron beams to make free electron lasers). The payoff, if you can
do this, is that the field components of focused laser beams from big
lasers (Shiva sized and larger) will give you very large accelerations
over relatively small distances.

There are many other schemes that have been mentioned as exotic
pipe dreams. If you are interested try looking through issues of Physics
Today and Science for semi-technical discussions. (I believe that the
Feb. issue of PT has a reasonable summary.)



				Steve Crandall
				mhuxt!evans