dietz@SLB-DOLL.CSNET (Paul Dietz) (12/10/85)
AWST (Dec. 9, page 18) reports that SDIO is claiming "incredible progress" in developing free-electron lasers at Livermore. The laser is large (100 meters long) but tunable and highly efficient (the article does not state the efficiency, but I've seen figures of 50% elsewhere). Recent tests in Hawaii have used automatic compensation for atmospheric turbulence to focus a low power laser on a missile in flight. The intention is to use this technology to direct a free electron laser beam to orbiting mirrors. According to the article, competing technologies, excimer and chemical lasers, are being deemphasized (I suppose because these would be less efficient, more massive and space based). While the utility of free-electron lasers for BMD is debatable, and the actual results obtained at Livermore unknown, FEL's are an ideal technology for more peaceful beamed power applications, such as powering electric engines in OTV's, supplying power to a lunar colony (or colonies) during the lunar night, or beaming power back from powersats. It is conceivable that we can use a ground-based FEL to deliver a continuous beam of light orders of magnitude more powerful than sunlight anywhere in cislunar space.
karn@petrus.UUCP (Phil R. Karn) (12/11/85)
> AWST (Dec. 9, page 18) reports that SDIO is claiming "incredible > progress" in developing free-electron lasers at Livermore. The I'm glad SDIO is able to make "incredible progress". That way they'll soon run out of toys to play with and run headlong into the fundamental issues, like the speed of light and the optical diffraction limit. Next thing we know, Abrahamson and Weinberger will announce an intensive research program into circumventing these two minor inconveniences. After all, they'll claim, nobody gave Einstein, who wasn't even an American for chrissake, the right to pass laws that true-blue Americans have to obey. "If we can land a man on the moon, why can't we travel faster than the speed of light?" I can hear it now. Phil
space@ucbvax.UUCP (12/12/85)
I would think that beam speading would limit the range of an electron beam severely. How does the FEL get around this?
space@ucbvax.UUCP (12/25/85)
A free electron laser does not emit free electrons, it uses free electrons to generate light (or microwaves, in which case it's a "microwave laser" like the original lasers were "optical masers" :-)) which can be beamed using big mirrors.