Counter Terror Expo round-upU.S. Army, law enforcement agencies, working on EMP grenades

Published 13 February 2009

Electromagnetic pulse, or EMP, has been typically associated with high-altitude nuclear explosions — explosions which disable electronic devices hundreds of miles away from the explosion; militaries and law enforcement want a hand-grenade-size EMP device for use in war and crime-fighting

By The term electromagnetic pulse, or EMP, became famous in the early 1960s. In July 1962 the United States conducted a 1.44 megaton U.S. nuclear test — called the Starfish Prime test — in space, some 400 kilometers above the mid-Pacific Ocean. The test demonstrated to nuclear scientists that the magnitude and effects of a high altitude nuclear explosion were much larger than had been previously calculated. Starfish Prime also made those effects known to the public by causing electrical damage in Hawaii, more than 800 miles away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms, and damaging a telephone company microwave link.

EMP is electromagnetic radiation from an explosion (typically, but not exclusively, a nuclear explosion) or an intensely fluctuating magnetic field caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the electronic or explosive device or in a surrounding medium. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. The effects are usually not noticeable beyond the blast radius unless the device is nuclear or specifically designed to produce an electromagnetic shockwave.

There are current concerns about EMP. Some security experts posit that a rogue state or a terrorist group may use nuclear weapons in an EMP attack on the United States. These worries were enough for the U.S. Congress to set up, in 2001, the United States EMP Commission (the commission was re-authorized in FY 2006). The commission is formally known as the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack.

Now, back to today. A U.S. Army electronic-warfare officer confirmed the existence of work by the U.S. Army on non-nuclear EMP ordnance. Bryant Jordan writes that the aim is to create a portable, hand-grenade-size version. The disclosure came at a blogger roundtable held in order to introduce the U.S. Army’s new electronic-warfare specialist career field. Col. Laurie Buckhout, chief of the newly formed Electronic Warfare Division, Army Operations, Readiness, and Mobilization, said:

EMP grenade technology is out there, but I’ve never had my hands on one. The Army needs to have its own on-the-ground assets to complement our abilities, to get the enemy first or stop them from getting us on the ground.Electronic warfare is going to be fought on the ground, not just in the air, and you have to have an attack from the ground point of view.

Lewis Page writes that the conventional method of generating an EMP powerful enough to disable electronics over a large area is the detonation of a nuclear weapon. Several militaries — but also law enforcement agencies —however, have been working on developing such a capability in smaller form (see this January 2008 High Energy Research and Applications (HERA)solicitation). This has led to extensive speculation on pulse bombs powered by conventional explosives, or High Powered Microwave (HPM) raygun-style kit (see, for example, statements by the U.S. Justice Department that its labs have built a “small working prototype” portable microwave rifle, potentially able to act as a tracking radar unit, a heat/pain raygun, or a millimeter wave through-clothes scanner).

References in the past to a pulse-bomb typically envisioned a rather large device, in the same league as an aircraft bomb or cruise missile warhead. HPM rayguns were seen as a weapons-pod or aircraft payload size. It was not clear from Colonel Buckhout’s words whether the U.S. military has already mastered the technique to miniaturize pulse bombs to the size of a hand grenade,

-read more about the U.S. Army electronic warfare specialty in Jamie Findlater, “Electronic Warfare Offers New Jobs for Tech-savvy Professionals,”, 12 February 2009.