LIVERMORE, Calif. — Laser weapons being developed as part of President Reagan's Strategic Defense Initiative could more easily be used to incinerate enemy cities than to protect the United States against Soviet missiles, according to an article in the current issue of a leading physics magazine and a separate study being circulated among government weapons scientists.
Many advocates of the "Star Wars" defense system hope lasers fired down from space stations or shot up from the Earth and reflected off space-based mirrors onto targets below may one day be part of a defensive shield against enemy missiles. But new analysis suggests that high-intensity laser light from such weapons could also be used offensively to unleash massive firestorms, possibly producing an environmental disaster similar to a "nuclear winter."
The study, which was produced by R&D Associates, an influential defense think tank based in Marina del Rey, cites data indicating that, "in a matter of hours, a laser defense system powerful enough to cope with the ballistic missile threat can also destroy the enemy's major cities by fire. The attack would proceed city by city, the attack time for each city being only a matter of minutes. Not nuclear destruction, but Armageddon all the same."
Lasers "have the potential of initiating massive urban fires and even of destroying the enemy's major cities by fire in a matter of hours," according to the article by Caroline L. Herzenberg, a government physicist at the Argonne National Laboratory near Chicago.
"Such mass fires might be expected to generate smoke in amounts comparable to the amounts generated in some major nuclear exchange scenarios," the article in the current issue of Physics and Society, a publication of the American Physical Society, warned. This could cause "a climatic catastrophe similar to 'nuclear winter,' " a reference to the disastrous lowering of the Earth's temperature many scientists believe would result from a nuclear war.
The R&D study does not mention a "nuclear winter" but does stress that lasers are not intrinsically defensive weapons and can be used offensively to start massive fires.
"The lasers can be employed in a manner not contemplated by the (Strategic Defense Initiative)," caution Albert L. Latter and Ernest A. Martinelli, who wrote the eight-page R&D Associates study and are highly regarded advocates of a stronger U.S. defense. "Specifically, they can be targeted against the same entities they were designed to protect: the cities.
Cities Held Hostage
"After spending hundreds of billions of dollars, we would be back where we started from: deterrence by retaliation. Our cities would be hostage to lasers instead of nuclear weapons," the report said.
President Reagan has offered ultimately to share "Star Wars" technology with the Soviet Union. But the R&D Associates report suggests that such weapons in the hands of the Soviets might prove menacing: "A Soviet laser weapon system . . . powerful enough to defend against the U.S. ballistic missile threat can incinerate our cities without warning on a time scale of minutes-per-city; minutes to hours for the whole country. To deter such an attack, the U.S. could only threaten to retaliate."
The authors suggested that laser weapons might also be used against Soviet conventional forces. "For those who have advocated limited nuclear options against the Soviet Union itself, limited laser options would produce less collateral damage and be just as effective otherwise," they wrote.
'Could Start Fires'
The danger of laser-induced fires had not been much noticed by critics or proponents of the Strategic Defense Initiative until the appearance of the article and the R&D study. When asked to comment, a Strategic Defense Initiative spokeswoman stated on a non-attribution basis after checking with other officials that "lasers could start fires." But she added that "this is not a problem that we are addressing at this time. It is not the intention of (the Strategic Defense Initiative) to start fires. This is an anti-ballistic (missile) program."
She denied also that lasers designed for defense could be used as offensive weapons. "They would have to be designed differently to cause fires," she said.
However, in an interview Friday, Herzenberg, the author of the physics magazine article, responded that "all you need is to dump enough energy on something and, if it's flammable, it will go up. The free electron laser, the excimer laser, and the deuterium fluoride chemical laser (which are the subjects of current research) all can go through the atmosphere and cause fires."
Lab Working on Lasers
The free electron laser is being developed at the Lawrence Livermore National Laboratory here. However, lab spokesman Norris Smith said that "the lab will have no comment" on the matter.
Theodore A. Postol, until recently adviser on nuclear weapons to the chief of naval operations and an expert on the implications of firestorms, said: "If you were attempting to set fires with an optical laser that was already sufficiently powerful to attack hardened ICBM boosters, there is no question that such a device could also be used to create mass fires of enormous scale and ferocity--mass urban fires potentially larger and more intense than those created by the great incendiary raids on Hamburg and Dresden in World War II."