"E-bomb" may see first combat use in Iraq 17:45 08 August 02 NewScientist.com news service Weapons designed to attack electronic systems and not people could see their first combat use in any military attack on Iraq. It is widely believed that the US is planning for an attack that could overthrow Iraq's leader, Saddam Hussein, who it believes is developing weapons of mass destruction. The Iraqi president responded publicly for the first time on Thursday, exhorting Iraqis to be prepared "with all the force you can to face your enemies". US intelligence reports indicate that key elements of the Iraqi war machine are located in heavily-fortified underground facilities or beneath civilian buildings such as hospitals. This means the role of non-lethal and precision weapons would be a critical factor in any conflict. High Power Microwave (HPM) devices are designed to destroy electronic equipment in command, control, communications and computer targets and are available to the US military. They produce an electromagnetic field of such intensity that their effect can be far more devastating than a lighting strike. Pumped flux The effect exploited by HPM weapons was accidentally demonstrated in the 1950s when street lights in Hawaii were knocked out by the electromagnetic pulse produced by high altitude nuclear tests. One unclassified approach to producing the required pulse is a device called an Explosive Pumped Flux Generator. In this a charged bank of capacitors energises a coil wrapped around a copper tube, which itself contains high explosives. On detonation, the explosives expand the tube from the back and moves rapidly forward, forcing the tube to make progressive contact with the coil and causing a short circuit. This has the effect of crushing the magnetic field at the same time as reducing the coil's inductance. The resultant spike lasts tens to hundreds of microseconds and can produce peak currents of tens of millions of Amps and peak energies of tens of millions of Joules. By comparison, a typical lighting strike produces around 30,000 Amps. Single use HPM weapons would be single-use and could be delivered on almost any a cruise missile or unmanned aircraft. Future devices are likely to be re-usable. Military planners will be particularly interested in claimed ability of HPM weapon's to penetrate bunkers buried deep underground by using service pipes, cables or ducts to transmit the spike. Insulating equipment from such spikes, for example by using Faraday cages, is believed to be very difficult and expensive. Another weapon that targets electronic equipment has already seen use in the Balkan conflicts of the 1990s. Blackout bombs, such as the formerly classified BLU-114/B, releases a spider's web of fine carbon filaments into the air above electrical distribution infrastructures. This causes short circuits when the filaments touch the ground. Tomahawk cruise missiles fitted with warheads operating on similar lines attacked the Iraqi power grid during the 1990 Gulf war. David Windle