Active Denial Technology (ADT) was the first non-lethal, directed-energy, counter-personnel system with an extended range greater than currently fielded non-lethal weapons. Most counter-personnel non-lethal weapons use kinetic energy (bullets, missiles). The Active Denial System provided military personnel with a non-lethal defense system on adversarial targets.
Image Credit: AFRL PRS History Office and Archives, Kirtland AFB NM