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By the end of this year, the Air Force plans to conduct a first, fully loaded test flight of its Airborne Laser, a jumbo jet packed with gear designed to shoot down enemy missiles half a world away, at the speed of light. The ABL also packs a megawatt-class punch--it's not exactly your garden-variety laser pointer.
For ground troops and embassy guards, meanwhile, a Humvee-mountable device with the nondescript name of Active Denial System is being put through its paces. The ADS would provide a nonlethal form of crowd control, using millimeter waves (a cousin of microwaves) to cause an intense--but noninjurious--burning sensation meant to encourage people to flee.
That's the plan for these ambitious directed-energy weapons, but for the moment they're still largely R&D works in progress.
One person who's been championing these efforts is Doug Beason, associate director for threat reduction at the Los Alamos National Laboratory and author of the 2005 book "The E-Bomb: How America's New Directed Energy Weapons Will Change the Way Future Wars Will Be Fought." Beason, a retired Air Force colonel who's also served as a science staffer at the White House, recently spoke with CNET News.com about getting a laser to shoot through the atmosphere and about down-to-earth weapons that give a high-tech hotfoot.
Q: What are the everyday uses of directed energy; what are people familiar with?
Beason: Directed energy really is just light that is part of the electromagnetic spectrum. It could be in the form of visible light, infrared light; it could be in microwaves; it could even be in radio waves, but there are two things that distinguish directed energy. First is that the light is coherent--the light all travels in the same direction--and the second thing is that the light is all in phase; imagine soldiers all marching to the same beat. We see directed energy in everyday uses. We see it in CD players--there are very tiny lasers, the diode lasers, in CD players--we see it in DVD players; we see it in the electronic or the infrared remotes that you have with your TV set. There are some stoplights now that use diode lasers. Fiber lasers are used for telecommunications.
Q: Is it simply a matter of scale, the difference between, say, a laser pointer and an Airborne Laser--just a much larger laser--or is there something else that goes on with that?
Beason: There are a couple of differences, but the scale is the biggest difference. A laser pointer typically has an energy of about 5 milliwatts, which is five one-thousandths of a watt, and Airborne Laser has a power on the order of megawatts, that is millions of watts, so it's a factor of about a billion times. There is another difference in that the laser pointer that you use consists of visible light, and the Airborne Laser uses infrared light. The only other differences come in how you handle that type of light--for example, you yourself can keep a laser pointer beam stable by pointing it just with your arm and kind of eyeballing where you want to keep the beam, but for the Airborne Laser, because you're broadcasting this beam over up to many hundreds of kilometers, you have to have a way to stabilize that beam. But in all practicality, the only difference between the laser pointer and the Airborne Laser is just the Airborne Lasers are a billion times more powerful.
And so the Airborne Laser is going through a new phase of testing--there's still ground testing going on now, and there's a plan for a flight test by the end of the year?
Beason: The Airborne Laser has actually flown, but without the laser inside of it. Now the laser has been put inside of it, and the laser has actually lased, that is, it achieved what they call "first light" last year. So it is undergoing testing now, and the first flight probably, if it doesn't happen this year, then it will be next year, because I think the first test of shooting down a tactical ballistic missile is supposed to take place in the time frame of 2008, and so that'll be the first time that what they call a "megawatt class" (laser gets tested).
And just to be clear--sometimes when we say Airborne Laser we're talking about the plane, and then it's also a description of a weapon itself.
Beason: That's right. What they really mean by the Airborne Laser is not the 747 that carries it, but the entire weapons system, that is the COIL laser--COIL stands for chemical oxygen iodine laser--the modified 747, as well as all the associated lasers that are on board. There are several other lasers that are onboard the Airborne Laser besides the weapons-class laser. There is a tracking laser, a laser that actually acquires the target, tracks the target. There is another laser that is there for the purpose of what is known as adaptive optics. If we were just to shoot the laser out over a distance without the beam being modified in some way, then the atmosphere would scatter the light; it would absorb the light, and by the time the beam hits the target, the beam would be in a very nonoptimum configuration--that is, it wouldn't be the most powerful energy density that you can put on a target. By using adaptive optics, what the Air Force has managed to do is to precondition the beam, so that it takes all the abnormal characteristics of the atmosphere out of the beam before it's propagated, and so by the time the beam reaches the target, it evolves into a very pristine, nearly optimal shape.
All aspects of this have been tested either in the laboratory or in the field. It's never really been put together as one package, and especially on the Airborne Laser as one system.
See more CNET content tagged:
laser,
microwave,
diode,
energy,
CD Player
A fascinating set of systems -- The evolution of Science, Science
Fiction and Imagination now coming to fruition.
DJO
"Beam" type energy weapons have been on the radar for a long time. There are various reasons why they aren't being used to the same extent as traditional firearms, but once their capabilities can honestly exceed those of traditional means, then the change will only take a matter of time.
I wrote about beam weapons last year:
http://www.inaniloquent.com/PermaLink.aspx?guid=8b31029f-76d0-4b26-b276-945efb836da8
If they don't have it already
If they don't have it already
Further, all the laws of physics, energy, thermal dynamics and inverse projection laws are fixed in this man's universe.
Interesting read, but still in the realms if science fiction!, such is life!
Further, all the laws of physics, energy, thermal dynamics and inverse projection laws are fixed in this man's universe.
Interesting read, but still in the realms if science fiction!, such is life!
The real test....can it pop a house's worth of popcorn?
The line about "Airborne Laser" already having flown without the actual laser is a crock, Why even mention that? No one cares that a 747 was capable of flight. That's like decades ago when there was supposed to be an experiment to test the feasibility of a nuclear powered aircraft. All they ended up doing was loading a small reactor (not hooked up to anything or providing any power) into a plane and flying around. Whoopee.
- Atmosheric effects on high power laser beams
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by leccleston
May 16, 2006 2:27 PM PDT
- From my past experiences with high powered lasers it is my understanding that the Lamb effect makes it very difficult to transmit extremely high power densities.
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See all 21 Comments >>We found back in the 60's that transmitting high powered laser pulses over 100 megawatts in peak power and in excess of 50 joules would result in breaking down the air. The leading edge would heat the air changing the index of refraction for the following energy and the pulse would actually shorten in length with the tail trying to catch up with the leading edge.
The energy density would get so high that the air would break down and absorb the rest of the pulse.
The answer of course was to increase the beam diameter but I still wonder what effect this laser will experience in the atmosphere.
I realize that there are atmospheric windows in the IR and that the density is much lower at high altitude but it still sounds like a challenge.
Larry Eccleston