"lightning gun" follows path of laser

The Army is working on a weapon that shoots "lightning." It uses a laser to create an plasma channel that the electricity follows.

Army looks to strike foes with lightning weapon | Fox News

Today's military lasers can blind spy satellites or burn enemy vehicles, but tomorrow's could guide lightning bolts to strike and destroy battlefield targets.

A U.S. Army lab is testing how lasers can create an energized plasma channel in the air — an invisible pathway for electricity to follow. The laser-guided lightning weapon could precisely hit targets such as enemy tanks or unexploded roadside bombs, because such targets represent better conductors for electricity than the ground.

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Oh wow, I had an idea similar to this quite some time ago, but wasn't quite sure how I could get a laser powerful enough to ionize the air, or create plasma.

If only I had access to incredibly expensive lab equipment...

Nice find. One day, I will build one.

AAlasers

Ahhh....Looks like WL is providing R&D to the US Military, again.

Maybe I'll run around with a real lightning gun. Maybe my dream of playing Quake in real life become semi real. lol

I remember a company had filed some patents for a laser guided taser. The laser was supposed to ionize a path for some sort of special frequency electric shock that would inhibit muscle response on humans and fry the computers of vehicles.

This was some 7 years ago, they claimed it would be available for sale shortly. Never heard of it again...

Is it just me or is this a little, pointless?

Any laser powerful enough to ionize air would be a far more potent, accurate & discreet weapon no?

But being able to zap computers that are hiding behind walls could be more useful than creating localized heating and/or ablation. I think the only benefit here is the change in direction.

ped said:

Is it just me or is this a little, pointless?

Any laser powerful enough to ionize air would be a far more potent, accurate & discreet weapon no?

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They mentioned road side bombs. So I'm going to assume this is portable. Portable in the sense you have one truck with the laser, and then another truck that follows close behind with the battery pack and various electrical devices needed to create a laser that powerful then you know.. the lightning...

Seems like they try to invent crazy expensive devices and then attempt to shoe horn them in to replace much less expensive ones that work just fine.

well, 2 M140 445nm diodes should work, because air scatters blue light much more than other colours, which is why the sky looks blue, the light you see as the "beam" is light that has been scattered, and the air inside the beam is partly ionised, giving it better conductivity than normal air, and the electricity passing through the beam further ionises it as the voltage drops. the brightness of the beam is a good measure of how much scattering is happening, and therefore how conductive the beam is.

the real issue is the conductivity of skin, which is extremely low. most tasers work because the hooks they fire puncture the skin, which provides a path through the skin for the electricity, and burnt skin conducts even worse.

its also pretty redundant, since if you're putting 2 watts of laser light into a target, the brightness alone will be more disorienting and painful than the electricity anyway

Do you have any references on 445nm ionizing air? I'd love to read about that

Atomicrox said:

Do you have any references on 445nm ionizing air? I'd love to read about that

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its all on wikipedia

when the light is scattered by the gases, the energy interacts with the gas, which momentarily ionises the gas, and then the energy gets re-emitted in random directions, allowing you to see the "beam" of the laser

in a dust/particulate free environment, the brightness of the beam is directly correlated with how ionised the air in the beam is.

Of course common scattering has nothing to do with ionization. You need high power densities to ionize air. Usually it's done by very short pulses. 2W 445nm will ionize nothing.

Here is some reading covering all aspects of the problem:

http://iopscience.iop.org/1367-2630/4/1/361/fulltext/

Yeah, I agree it has nothing to do with scattering.
That's a nice paper, lots of cool stuff. Didn't know about that Kerr self focusing effect.
Unfortunately with those parameters we'll never be able to do any air ionization with pointers :/