The Army's new ray gun research project combines the zap of a laser with the crackle of an electric shock and the pop of a high-power microwave pulse. Known as the Multimode Directed Energy Armament System, it offers a wide range of different effects against different targets. Defensively, it could knock out everything from improvised explosive devices to incoming rockets. As a weapon, its effects might range from Taser-like effects to a lethal lightning bolt – and it should be able to stop vehicles in their tracks. Assuming the tech all pans out as planned, naturally.

The technology, which I describe in this week's New Scientist magazine, uses an ultra-short pulse laser to create an ionized channel through the air; down this channel, you can then send bursts of energy. It'll conduct electricity. And it can also act as a waveguide for an intense pulse of microwaves. These could be used to destroy the fuze of a roadside bomb, fry the electronics of a missile, or burn out the ignition on any unshielded vehicle.

(In a way, the Multimode system is a new twist on the devices developed by Applied Energetics, formerly Ionatron. But that firm, which promised "laser-guided man-made lightning," has been notably unsuccessful in actually fielding anything that works so far. Plus they've been accused of what might politely be termed controversial business practices. And unlike Ionatron's "Joint IED Neutralizer" – a vehicle-mounted device with an apparent range of just three feet, backers of the the new Multimode system promise it'll be portable, with a much greater effective range.)

According to this presentation given by Barbara Machiak the Army's Armament Research Development and Engineering Center (ARDEC), the device "defeats/neutralizes full spectrum of materiel threats at stand off," offers "multi-mode DE [directed energy] effects from one platform for anti-personnel and anti-material" and has "scalable effects from non-lethal to lethal."

This raises all sorts of questions. What would that "full spectrum"

of threats include? Does this mean we will have a portable, lethal ray

gun sending deadly electric pulses down a glowing ionized laser

filament? ARDEC would not discuss the project in any detail – and if

you look closely at that presentation, you'll see one significant image

has been scratched out for reasons of security. However, ARDEC does

acknowledge that it exists and that its first mission will be to take

out IEDs. They aim to have a demonstrator working in a realistic

environment in FY2011.

Danger Room asked Carlo Kopp – an assistant professor at Monash

University of Melbourne and an expert on electromagnetic pulse weapons

\– about the idea of using the laser ionization channel (technically

known as a Laser Induced Plasma Channel or LIPC) to direct a microwave

pulse. He believes that the physics are straightforward enough, and

compared it to using a taut metal wire as a waveguide, although

engineering may be a challenge.

"Conventional HPM [High Power Microwave] is inverse square law range

limited, LIPC is plasma channel cohesion range limited," Prof. Kopp

notes. This suggests that if ARDEC can create a long enough channel (a

big if), this technology might be able to precisely deliver a microwave

pulse to a point target at extended range, rather than blanketing a

wide area.

It may also have one other key advantage, says Prof. Kopp. High-powered microwave antennas have

a tendency to spill to the back and the side, "producing 'self kill' on

the delivery platform. If an LIPC scheme solves this problem it is

worth the extra complexity and cost."

At present, the U.S. military is reluctant to put high-power microwave weapons on manned platforms

because of this risk of "self kill." So the new technology might be a

major step forwards. However, ARDEC are not the only ones working on

this technology. A Canadian team published a paper on a very similar project

last year –- except that they specify using an array of plasma

waveguides to form a hollow cylinder to contain the microwaves, and

theirs was strictly a lab experiment. Two of the researchers come from

Defence R&D Canada though, so the military applications are

probably not lost on them.

And if the idea of microwaves being channeled along a laser beam sounds familiar, Then the MEDUSA "mobile energy device" which Sharon described back in 2007

works on the same basic principle " Microwave transmission using a

laser-generated plasma beam waveguide" – except that was an unfunded

scheme put forward by an unknown start-up company. (Defense contractor BAE Systems' Laser/microwave combination

weapon mentioned a couple of years ago is not related, that just uses a

laser in the control circuitry to improve the coherence of the

microwave beam.)

I have come across a number of other U.S. Army projects that appear to feed into the Multimode Weapon program, relating to lasers, microwave sources and pulsed power. This makes it difficult to assess the overall budget and how long it has been under development - it's at least nine years plus. But if the research develops into something battlefield-worthy – a big if – it might be quite a big deal. Perhaps we'll see a one-shot portable bomb-zapper. Or perhaps a weapon that could be very dangerous indeed.

[Image: Joint Nonlethal Weapons Directorate]