The United States most likely has EMP weapons in its arsenal, but it's not clear in what form. Much of the United States' EMP research has involved high power microwaves (HPMs). Reporters have widely speculated that they do exist and that such weapons could be used in a war with Iraq.
Most likely, the United States' HPM e-bombs aren't really bombs at all. They're probably more like super powerful microwave ovens that can generate a concentrated beam of microwave energy. One possibility is the HPM device would be mounted to a cruise missile, disrupting ground targets from above.
This technology is advanced and expensive and so would be inaccessible to military forces without considerable resources. But that's only one piece of the e-bomb story. Using inexpensive supplies and rudimentary engineering knowledge, a terrorist organization could easily construct a dangerous e-bomb device.
In late September 2001, Popular Mechanics published an article outlining this possibility. The article focused on flux compression generator bombs (FCGs), which date back to the 1950s. This sort of e-bomb has a fairly simple, potentially inexpensive design, illustrated below. (This conceptual bomb design comes from this report written by Carlo Kopp, a defense analyst. The design concept has been widely available to the public for some time. Nobody would be able to construct a functioning e-bomb from this description alone).
The bomb consists of a metal cylinder (called the armature), which is surrounded by a coil of wire (the stator winding). The armature cylinder is filled with high explosive, and a sturdy jacket surrounds the entire device. The stator winding and the armature cylinder are separated by empty space. The bomb also has a power source, such as a bank of capacitors, which can be connected to the stator.
Here's the sequence of events when the bomb goes off:
- A switch connects the capacitors to the stator, sending an electrical current through the wires. This generates an intense magnetic field.
- A fuze mechanism ignites the explosive material. The explosion travels as a wave through the middle of the armature cylinder.
- As the explosion makes its way through the cylinder, the cylinder comes in contact with the stator winding. This creates a short circuit, cutting the stator off from its power supply.
- The moving short circuit compresses the magnetic field, generating an intense electromagnetic burst.
Most likely, this type of weapon would affect a relatively small area -- nothing on the order of a nuclear EMP attack -- but it could do some serious damage.
In the next section, we'll look at some possible effects of an EMP attack.