The Pentagon has unveiled a new non-lethal ray gun for use against rioters which disables victims by making them feel as if their clothes are about to catch fire.
The weapon fires beams of concentrated but harmless heat from a large dish antenna mounted on a Humvee jeep and is effective at up to 500 yards. At 130°F, the invisible microwave beam feels like a blast of sudden, midday desert heat and can cause armed targets to drop their weapons and begin to peel off their clothes.
The system uses millimetre waves capable of penetrating the outer layers of human skin just enough to cause discomfort without inflicting damage.
By comparison, a kitchen microwave oven emits radiation which can penetrate several centimetres of human flesh, inflict burns and destroy cells. Christened the Active Denial System, the weapon is not due to enter service until at least 2010.
The US military and a number of law enforcement organisations foresee its deployment for riot control, covering roadblocks, and even defending the perimeters of army bases.