brucec@orca.UUCP (Bruce Cohen) (08/01/83)
Please remember that to do significant damage to an incoming ICBM, a short wavelength laser needs to be very tightly focused, and must be optimized for very short pulsewidths (long pulses will vaporize sufficient target material to form a shield against the laser radiation). The radiation damage of the laser is intended to 1) knock out the guidance electronics of the warhead, or 2) damage the airframe of the warhead sufficiently to cause it to tumble and burn on re-entry. If shooting at an ascending booster, the intent is to hole the fuel system or airframe, causing the booster to either explode or go off course. No laser system that I know of is envisioned as being capable of vaporizing a large fraction of the mass of a warhead. As far as particle beams go, I seriously doubt that they can do any real damage over distance in the atmosphere, because of absorption and defocusing (see the article by Kosta Tsipis on particle beam weapons in Scientific American in the lsat couple of years). Such weapons are highly ineffective against large targets like cities or ground vehicles. I doubt that they could even do significant damage to a concrete building. (Infrared lasers can cut through concrete right now, if used in continuous mode, but such lasers are not effective against reflective metal nosecones. A person standing out in the street would very likely be killed instantly by such a beam, but the person standing ten feet away might be unscathed. Moreover, ground targets can dodge mush faster than ICBM warheads, whose incoming speed makes changing aiming angle from an oncoming beam very slow. Bruce Cohen UUCP: ...!teklabs!tekecs!brucec CSNET: tekecs!brucec@tektronix ARPA: tekecs!brucec.tektronix@rand-relay