Microwave Weaponry, High Power (HPM)

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Microwave Weaponry, High Power (HPM)

High-power microwave (HPM) weaponry sends out a short, extremely high-voltage burst of electromagnetic energy capable of disrupting computer systems for a fraction of a second. Although the disruption is short, the burst causes computers to reset, and if the computers operate something as sensitive as the control and navigation systems of a jet in mid-flight, the result could be lethal. HPM systems are effective weapons by virtue of the fact that their use is difficult to trace. For technologically sophisticated powers such as the United States, however, HPM weapons are potentially as much of a threat as they are an asset.

HPM capabilities. If HPM simply shut down computer systems, that might be enough to make them formidable weapons, but their usefulness does not stop there. As anyone who has ever accidentally put a piece of metal in a microwave oven knows, metal in contact with micro-waves tends to spark. If the conductive wire harness inside an airplane fuel tank were hit with a microwave near the end of a transoceanic flight, when the concentration of fumes in the tank is heavy, the result could be an explosion.

To further the threatening quality of HPM weaponry, these systems use "ammunition"—electromagnetic energy—that is invisible, travels at the speed of light, and exists in virtually limitless supply. Nor does an HPM beam leave any markings, like the spent round of a traditional weapon, that would connect it to the weapon that fired it.

HPM uses. Until the 1970s, HPM technology was impractical. Over the next two decades, however, developments in plasma physics, energy storage, and the technology of switching devices made these weapons systems viable around the time the Cold War came to an end. The Soviets invested more research in the field than did the West, a logical choice because HPM weaponry is more useful to the less technologically advanced side. The more sophisticated a nation's weapons systems, and the more reliant on microprocessors, the more vulnerable these potentially are to HPM.

Russian authorities claimed that in 1995, Chechnyan rebels used HPM to subvert a Russian security system and gain entry to a restricted-access area. Four years later, the Russians maintained that United States forces used HPM weapons to disable Yugoslav communications during the North Atlantic Treaty Organization (NATO) campaign in Kosovo.

Carbon-graphite coils capable of generating an electromagnetic pulse used to destroy electronics equipment—especially communications equipment—can be fitted to cruise missiles. Carbon-graphite equipped cruise missiles were used by U.S.-led forces in raids on Baghdad, Iraq, in 1991 and in 2003.

Scientists at Lawrence Livermore National Laboratory also have developed an HPM weapon for the Department of Justice: aimed at a moving vehicle, the HPM could shut off the electronic ignition, thus bringing a high-speed car chase to an abrupt end.

American use of HPM systems carried with it the threat that enemies might gain access to such weapons as well. In view of this danger, the Department of Defense took steps to "harden" the electronic circuitry of weapons to protect them against attacks.