According to Andy Mazzara, the director of the Institute for Non-Lethal Defence Technologies at Pennsylvania State University, prototypes of such devices use a laser to create an ionised channel of air through which an electromagnetic pulse is directed.

ECONOMIST: Monitor

The future of clean tech is already looking bright, as the world's solar power capacity just hit a record 101 gigawatts, and researchers found a new way to charge batteries by harvesting ambient electromagnetic waves from thin air.

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He pointed out that Professor Henshaw's experiments were carried out in the open air, and that houses provided natural "shielding" from the electromagnetic fields.

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Early research involved a colleague lying in a deckchair in the night-time open air with a piece of string to measure the meteors, while he observed electromagnetic signals on a cathode-ray tube in a nearby hut.

ECONOMIST: Bernard Lovell | The

While some of these weapon and sensor systems like the Electromagnetic Railgun or the Free Electron Laser are at least a decade away, the Laser Weapon System and Air and Missile Defense Radar systems are almost ready for prime time deployment today.

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