Electromagnetic weapons designed to zap circuitry have long been a favourite speculation of war-tech buffs. Consensus opinion suggests that the only energy source capable of powering a useful pulse strike is a nuclear explosion, or perhaps in the near future a largish conventional bomb. But a recent report in MIT Tech Review suggests that actually it can be done with a car alternator.
The Tech Review piece introduces us to Eureka Aerospace and its High power Electromagnetic System (HPEMS) tech, now being touted as a good idea for police in high speed chases. Apparently, a 200lb, six by three foot HPEMS module can "be attached to an automobile or aircraft carrier" (though the aircraft-carrier option might be a tad unwieldy on the freeway). It works like this:
The car's alternator serves as the system's power source [cool! You just plug it into the cigarette lighter socket, presumably]... pulses are amplified to 640 kilovolts using a 16-stage Marx generator... then converted into microwaves using... a pair of coupled transmission lines and several spark-gap switches. Finally, a specially designed antenna beams the microwave energy toward an opposing vehicle...
The microwaves get into the fleeing villains' engine compartment through some kind of unspecified gap in the metal that would typically surround it, and zap all the microcircuitry, so shutting the motor down.
Tech Review notes that this might cause some snags by frying innocent people's stuff in a crowded urban environment, but otherwise it seems to assume that the idea is a flyer.
In fact, all the signs of a tech turkey are there. The obvious customer - the US military* - funded initial research and then gave up some time ago. Even the company doesn't claim effective range greater than 15 metres, so a pursuing cop would have to get well inside safe stopping distance behind a fleeing car - just before forcing it to stop suddenly. All tests thus far have been on stationary target vehicles. The only way of aiming the directional beam is by aiming the car. Years have gone by and nothing much has changed.
Nope - this thing's a gobbler, and a cold dead one at that. The MIT tech scribes seem to have slipped up here. ®
*A mysterious outfit called the "U.S. Marine Corp [sic]" is referred to twice.