Oct 15th, The Economist
BULLETS and bombs are so 20th-century. The wars of the 21st will be dominated by ray guns.
High-Powered MicrowaveThat, at least, is the vision of a band of military technologists who are building weapons that work by zapping the enemy’s electronics, rather than blowing him to bits.
Electromagnetic weapons [...] are inspired by the cold-war idea of using the radio-frequency energy released by an atom bomb exploded high in the atmosphere to burn out an enemy’s electrical grid, telephone network and possibly even the wiring of his motor vehicles, by inducing a sudden surge of electricity in the cables that run these things.
[...] military planners have developed weapons that use a similar principle, without the need for a nuclear explosion. Instead, they create their electromagnetic pulses with magnetrons, the microwave generators at the hearts of radar sets (and also of microwave ovens). The result is kit that can take down enemy missiles and aircraft, stop tanks in their tracks and bring speedboats to a halt. It can also scare away soldiers without actually killing them.
Many electromagnetic weapons do, indeed, look like radars, at least to non-expert eyes. America’s air force is developing a range of them based on a type of radar called an active electronically scanned array (AESA). When acting as a normal radar, an AESA broadcasts its microwaves over a wide area. At the touch of a button, however, all of its energy can be focused onto a single point. If that point coincides with an incoming missile or aircraft, the target’s electronics will be zapped.
In 2013 America hopes to deploy the Radio-Frequency Vehicle Stopper. This device [...] is a microwave transmitter the size and shape of a small satellite dish that pivots on top of an armoured car. When aimed at another vehicle, it causes that vehicle’s engine to stall.
This gentle way of handling the enemy—stopping his speedboats, stalling his tanks—has surprising advantages. For example, it expands the range of targets that can be attacked. Some favourite tricks of modern warfare, such as building communications centres in hospitals, or protecting sites with civilian “human shields”, cease to be effective if it is simply the electronics of the equipment being attacked that are destroyed. Though disabling an aircraft’s avionics will obviously cause it to crash, in many other cases, no direct harm is done to people at all.
The logical conclusion of all this is a so-called “human-safe” missile, which carries an electromagnetic gun instead of an explosive warhead. Such a missile is being developed at Kirtland Air Force Base in New Mexico, and will soon be tested at the White Sands Missile Range.
There is, however, at least one electromagnetic weapon that is designed to attack enemy soldiers directly—though with the intention of driving them off, rather than killing them. This weapon, which is called the Active Denial System, has been developed by the Joint Non-Lethal Weapons Directorate, in collaboration with Raytheon. It works by heating the moisture in a person’s skin to the point where it feels [...] like opening a hot oven. People’s reaction, when hit by the beam, is usually to flee. The beam’s range is several hundred metres.
Such anti-personnel weapons are controversial. Tests on monkeys, including ones in which the animals’ eyes were held open to check that the beam does not blind, suggest it causes no permanent damage. [...]
To every action there is, of course, an equal and opposite reaction, and researchers are just as busy designing ways of foiling electromagnetic weapons as they are developing them. Most such foils are types of Faraday cage—named after the 19th-century investigator who did much of the fundamental research on electromagnetism.
A Faraday cage is a shield of conductive material that stops electromagnetic radiation penetrating. Such shields need not be heavy. Nickel- and copper-coated polyester mesh is a good starting point. Metallised textiles—chemically treated for greater conductivity—are also used. But Faraday cages can be costly. EMP-tronic, a firm based in Morarp, Sweden, has developed such shielding, initially for the Gripen, a Swedish fighter jet. It will shield buildings too, though, for a suitable consideration. To cover one a mere 20 metres square with a copper-mesh Faraday cage the firm charges €300,000 ($400,000).
Shielding buildings may soon become less expensive than that. At least two groups of scientists—one at the National Research Council Canada and the other at Global Contour, a firm in Texas—are developing electrically conductive cement that will block electromagnetic pulses. Global Contour’s mixture, which includes fibres of steel and carbon, as well as a special ingredient that the firm will not disclose, would add only $20 to the $150 per cubic metre, or thereabouts, which ordinary concrete costs.
The arms race to protect small vehicles and buildings against electromagnetic warfare, then, has already begun.[...]