A military convoy is making its way through a crowded Baghdad street. Without warning, a blast rings out and the Bradley fighting vehicle leading the convoy is destroyed, along with the men and women it carried.
A crowd of what appears to be civilians rushes the decimated vehicle, surrounding it, and units are called in to calm the situation and secure the Bradley. The crowd grows unruly. Units on the scene fear that insurgents or sympathizers may have blended into the crowd and are attempting to loot the vehicle of ammunition and parts.
Today, those units have two choices -- and both of them are bad. They can attempt to disperse the crowd by ordering them to get away from the vehicle -- which would likely have little effect -- or they can fire into the crowd, possibly injuring or even killing innocent civilians in the process.
"If you're a soldier dealing with an unruly mob, you don't have a lot of options," says Noah Shachtman, editor-in-chief of Defensetech.org. "You have the M-16 option, the bullhorn option, and there's not that much in between."
That is, until now. A new non-lethal weapon developed by the Department of Defense intends to give soldiers a third option in these situations.
The ADS, or Active Denial System, fires an invisible beam that penetrates the top 1/64th of an inch on a target's skin, hitting sensitive pain receptors and causing a burning sensation some have likened to being dipped in molten lava.
When the target steps out of the beam's path, the pain goes away instantly, causing no permanent damage and leaving no marks, bruises or burns.
Some military experts are calling it the Holy Grail of crowd control. But critics fear that after incidents like the Abu Ghraib prison torture scandal, the potential for the technology to be used for more sinister means is simply too great.
"The big concern is exactly what it's going to be used for and do we want a weapon that simply causes pain because there are all sorts of ways that this could be misused," said David Hambling, who has monitored the ADS and other non-lethal technologies and written the book "Weapons Grade: How Modern Warfare Gave Birth to Our High-Tech World."
The ADS looks like a flat radar dish mounted on a military Hummer. Engineers are also developing an airborne, shipboard and hand-held version as well. Operators use a focused camera that shows exactly where the beam will hit and fire on targets from afar, keeping the device and the soldiers around it out of range of small arms fire.
"If you've ever used a blow dryer on your hair, and if you leave the blow dryer in one place for too long, you have to move it away -- it's very similar to that effect," said Susan LeVine, principle deputy for policy and strategy at Defense Department's Joint Non-Lethal Weapons Program.
The device uses millimeter waves that are much easier to control than microwaves but have a similar effect -- they heat things up.
LeVine insisted that millimeter waves are not nearly as harmful as microwaves -- though both can cause cancer. She said extensive testing has proven that the device isn't dangerous beyond the pain it generates.
"It does not penetrate or reach deep into the body, so it's not going to affect your internal organs or pacemaker -- it's only going to touch the outermost surface of the skin," she said. "This is by far the most researched non-lethal weapon in the history of the Department of Defense."