The U.S. military demonstrated a new weapon Wednesday designed to disperse crowds: a heat-ray gun that makes people feel as if they are about to catch fire.

The ray gun for crowd control goes by the unwieldy name of "active denial system" but it sounds like science fiction: its beam makes people feel intense heat.

An airman looks over the military's Active Denial System, a non-lethal ray gun demonstrated Wednesday at Moody Air Force Base, Ga.
(Elliott Minor/Associated Press)

Apart from causing that terrifying sensation, the technology is supposed to be harmless – a non-lethal way to get enemies to drop their weapons.

Military brass said it could save lives in places like Iraq and Afghanistan.

During the weapon's first media demonstration yesterday at Moody Air Force Base in Georgia, airmen fired beams from a large dish antenna mounted atop a Humvee at people pretending to be rioters and acting out other scenarios troops might encounter in war zones.

The device's two-man crew located their targets through powerful lenses and fired beams from more than 500 metres away, which is nearly 17 times the range of existing non-lethal weapons, such as rubber bullets.

Anyone hit by the beam immediately jumped out of its path because of the sudden blast of heat felt throughout the body. While the 54 C heat was not painful, it was intense enough to make the participants think their clothes were about to ignite.

Production slated for 2010

The weapon is not expected to go into production until at least 2010, but all branches of the military have expressed interest in it, officials said.

"This is one of the key technologies for the future," said marine Col. Kirk Hymes, director of the non-lethal weapons program at Quantico, Va., which helped develop the new weapon.

"Non-lethal weapons are important for the escalation of force, especially in the environments our forces are operating in," he said.

The system uses millimetre waves that penetrate only 0.4 millimetres into skin, just enough to cause discomfort. By comparison, microwaves used in the common kitchen appliance can penetrate five or more centimetres through skin.

Such a ray gun could be mounted aboard ships, airplanes and helicopters, and routinely used for security or anti-terrorism operations.

"There should be no collateral damage to this," said Senior Airman Adam Navin, 22, of Green Bay, Wis., who has served several tours in Iraq.

Navin and two other airmen were role players in the demonstration, along with 10 reporters who volunteered to be shot with the beams. The beams easily penetrated various layers of winter clothing.

Airman Blaine Pernell, 22, of New Orleans, said he could have used the system during his four tours in Iraq, where he manned watchtowers around a base near Kirkuk. He said Iraqis constantly pulled up and faked car problems so they could scout out U.S. forces.

"All we could do is watch them," he said. But if they'd had the ray gun, troops "could have dispersed them."