CORRECTED: U.S. eyes heat-beaming weapon by 2010

Corrects final paragraph to clarify that more than 600 human volunteers were exposed to the ray a total of more than 10,000 times, from more than 10,000 people had been exposed

By Jim Wolf

MOODY AIR FORCE BASE, Georgia (Reuters) - The U.S. Defense Department on Wednesday unveiled what it called a revolutionary heat-beaming weapon that could be used to control mobs or repel foes in conflicts like Iraq and Afghanistan.

The so-called Active Denial System causes an intense burning sensation causing people to run for cover, but no lasting harm, officials said.

"This is a breakthrough technology that's going to give our forces a capability they don't now have," Theodore Barna, an assistant deputy undersecretary of defense for advanced systems and concepts, told Reuters. "We expect the services to add it to their tool kit. And that could happen as early as 2010."

The weapon, mounted on a Humvee, uses a large rectangular dish antenna to direct an invisible beam toward a target. It includes a high-voltage power unit and beam-generating equipment and is effective at more than 500 meters.

Existing counter-personnel systems designed not to kill -- including bean bag munitions and rubber bullets -- work at little more than "rock-throwing distances," said Marine Col. Kirk Hymes, director of the Pentagon's Joint Non-Lethal Weapons Directorate.

In increasingly complex military operations, the technology provided a much-needed alternative to just going from "shouting to shooting," said Hymes, who is responsible for the weapon's five-year, $60 million advanced development.

Variations of the system could help in peacetime and wartime missions, including crowd control and mob dispersal, checkpoint security and port protection, officials said. It could also help in conflicts like Iraq and Afghanistan.

Raytheon Co., which has worked to develop the technology, has built a prototype called Silent Guardian, that it hopes to sell in the United States and abroad in what could become a multibillion market.

The weapon was shown off publicly for the first time at Moody Air Force Base in Georgia, where it has been undergoing operational tests by the 820th Security Forces Group, which protects Air Force assets.

The directorate invited reporters to be zapped as part of what its spokeswoman, Marine Maj. Sarah Fullwood, called an effort to "demystify" the technology at issue.

At a distance of several football fields, the sensation from the exposure was like a blast from a very hot oven, too painful to bear without scrambling for cover.

The burning sensation is achieved by high-power energy waves that heat the skin to 130 degrees Fahrenheit. The pain ended as soon as the target jumped from the line of fire.

Documents given out during the demonstration said more than 600 volunteers were exposed to the ray a total of more than 10,000 times since testing began over 12 years ago. They said there had been no injuries requiring medical attention during the five-year advanced development program.