For years, the U.S. military has explored a new kind of firepower that is instantaneous, precise and virtually inexhaustible: beams of electromagnetic energy. "Directed-energy" pulses can be throttled up or down depending on the situation, much like the phasers on "Star Trek" could be set to kill or merely stun.

Such weapons are now nearing fruition. But logistical issues have delayed their battlefield debut -- even as soldiers in Iraq encounter tense urban situations in which the nonlethal capabilities of directed energy could be put to the test...

...The directed-energy component in the project is the Active Denial System, developed by Air Force researchers and built by Raytheon Co. It produces a millimeter-wavelength burst of energy that penetrates 1/64 of an inch into a person's skin, agitating water molecules to produce heat. The sensation is certain to get people to halt whatever they are doing.

Military investigators say decades of research have shown that the effect ends the moment a person is out of the beam, and no lasting damage is done as long as the stream does not exceed a certain duration. How long? That answer is classified, but it apparently is in the realm of seconds, not minutes. The range of the beam also is secret, though it is said to be further than small arms fire, so an attacker could be repelled before he could pull a trigger...

...Bitar heads Indiana-based Xtreme Alternative Defense Systems Ltd., which makes small blinding lasers used in Iraq. But his real project is a nonlethal energy device called the StunStrike.

Basically, it fires a bolt of lightning. It can be tuned to blow up explosives, possibly to stop vehicles and certainly to buzz people. The strike can be made to feel as gentle as "broom bristles" or cranked up to deliver a paralyzing jolt that "takes a few minutes to wear off."

Bitar, who is of Arab descent, believes StunStrike would be particularly intimidating in the Middle East because, he contends, people there are especially afraid of lightning.

At present, StunStrike is a 20-foot tower that can zap things up to 28 feet away. The next step is to shrink it so it could be wielded by troops and used in civilian locales like airplane cabins or building entrances...