Free Electron Laser

[Mr Monkeybat]

Im guessing that between the reactors and the FEL will be some big super capacitors for energy storage.

 

One advantage of the FEL other other laser is that as the lasing medium is already a magnetically confined plasma you dont have to worry about it melting so instead of directing the beam with mirrors or prisms which can also melt I wonder if it possible to mount the FEL on a turret.

 

About the canon ball idea, in order for a battleship to get within artillery range it would need its own FEL to shoot down all the planes and missiles that a carrier group has at its disposal. Even that giant rail gun has less ballistic range than than a carrier groups planes and missiles. You can also mount a kinetic penetrator on a ballistic missile but realize that a you dont have to entirely rely on photon pressure to change the projectiles course as the ablation of the projectiles surface provides reaction mass and changes its aerodynamic profile when it reaches the atmosphere.

[swansont]

A short while ago I was absolutely FLOORED as I watched the U.S. Navy target a small rocking boat at sea with a low poer FEL. It was able to target the craft as well as keep a beam lock upon a specific point on this rocking boat. I NEVER thought the FEL would be made public so soon.

 

 

Locking on a target is much more about the target tracking system than the laser. Also, missiles move faster than boats. The R&D has to scale this up and then get to a deployable system (i.e. robust and operable/maintainable by sailors rather than techs). This not a weapon that is ready to be included on ships.

 

 

One advantage of the FEL other other laser is that as the lasing medium is already a magnetically confined plasma you dont have to worry about it melting so instead of directing the beam with mirrors or prisms which can also melt I wonder if it possible to mount the FEL on a turret.

 

For tracking-speed purposes I'd expect you'd want to go away from a turret mount for the laser itself.

[SplitInfinity]

 

 

Locking on a target is much more about the target tracking system than the laser. Also, missiles move faster than boats. The R&D has to scale this up and then get to a deployable system (i.e. robust and operable/maintainable by sailors rather than techs). This not a weapon that is ready to be included on ships.

 

 

 

For tracking-speed purposes I'd expect you'd want to go away from a turret mount for the laser itself.

 

I am fairly certain from what I have been told that the current issue as far as installing an FEL system on U.S. Carriers and Cruisers is more about the ability of the 2 A1B Nuclear Reactors to properly supply power forthe carrier as well as the FEL.

 

The A1B's were designed originally for just the carrier and the possible addition of Cloaking Panels that may be added as well as deployable Screens that would show a picture of what is behind the carrier from a variety of angles. This tech is not all that big a deal but having giant rollout screens that a live picture could be displayed presents MANY problems given the size, geometry and wind and salt water that would be effecting them.

 

Such a system is known to have been installed on a Lockheed Stealth Blimp...but these paneled screens are right on the skin of this craft.

 

The A1B's have already been changed and huge amounts of money have been spent in their development as well as many have been given a GO for purchase. It is going to take a much greater amount of power generated to properly power the FEL.

 

The HEAT issue...I have heard that was a problem that was solved at great cost. The Sat. system has to use Prisms in the design of insect like multiple compound eyes as standard optics or mirrors vaporise upon contact.

 

Targeting and aquisition seem to be a done deal. It is said that Split Beaming to achieve multiple kills of multiple targets can be achieved using the Prism Sat. system but I don't exactly know how they intend to do this without using the Sat.

 

I also herd that they might add a Third Reactor on Carriers although I have no idea where they would put this.

 

Split Infinity

[swansont]

Unsourced information is not particularly compelling. I don't what what you've heard, especially when it doesn't jibe with information that's publicly available.

 

———

 

"thus bringing a shipboard FEL closer to realization" is not what you say about a system that's ready to go on board a ship.

 

http://detroit.cbslocal.com/2012/12/11/niowave-breakthrough-advances-u-s-navy-free-electron-laser-program/

 

Being funded through ONR means it has all the hallmarks of being a research program, with several people getting funding, in order to come up with the best solution. Not something being produced, ready to deploy.

 

Also, from 1 year ago:

http://www.wired.com/dangerroom/2012/03/navy-lasers-four-years/

"Within four years, they claim they’ll have a working prototype of a laser cannon, ready to place aboard a ship."

 

A working prototype is still (at least) 3 years away, according to that. R&D rarely jumps ahead of schedule. Also, the motorboat targeting test was a 15 kW device. That's a far cry from 1 MW, or even the 100 kW mentioned as being "militarily useful"

[John Cuthber]

OK...I will restate this.

 

The Ford Class carriers will have Free Electron Lasers installed. The current reactors will be two A1B's which will probably be replaced by two or perhaps even three more powerful reactors.

 

The carriers FEL systems will be used along with a Satellite Targetng system for both Carrier Defense and Offense but mainly used for Anti-missile...Anti-aircraft defense which they will be VERY adept.

 

The statement as far as the 1000 feet steel statement was a theoretical one where if enough power was available the FEL could vaporize a hoe quickly through it. This would not be carrier based.

 

The carrier FEL along with a sat system should be able to easily destroy ground based and ship based radar and other electronic systems specific to tracking and targeting as well as capable as an ani-personal weapon.

 

Split Infinity

The statement about the 1000 feet is just silly on two sets of grounds.

There isn't a thousand foot thick target to aim at and it would be outside of the capability of the largest nuclear reactor in the world to supply power for it.

 

"The carrier FEL along with a sat system should be able to easily destroy ground based and ship based radar and other electronic systems specific to tracking and targeting as well as capable as an ani-personal weapon."

So, a bit like a gun then?

 

"A short while ago I was absolutely FLOORED as I watched the U.S. Navy target a small rocking boat at sea with a low poer FEL. It was able to target the craft as well as keep a beam lock upon a specific point on this rocking boat."

How could you tell?

Oh, yes, probably because you were able to (instinctively) keep your eyes pointed at the boat.

Impressive when it was new- but I think that was many millions of years ago.

[swansont]

I think the 1000 feet in a second* is a poorly-worded blurb on the part of whomever was the public relations person. I think they were giving a rate of cutting. I doubt the navy ever wanted to give the impression they were ever thinking about cutting through super-thick targets. But the link I found above says 20 feet in 1 second for 1 MW, which is a lot more plausible. That's about a quarter inch per ms, meaning the time to zap an incoming missile is short, which is the whole point of the system — you don't want to have to hit the same spot with the laser for very long.

 

*if that's an accurate number. Thus far SplitInfinity has failed to give even a single link to supporting information for the claims, and since some claims have been demonstrably wrong I'm happy to call BS on all of the non-obvious ones, pending some kind of reference.

[ACG52]

The actual quote was

Discover Magazine has reported that this Nuclear Reactor power supplied Free Electron Laser can vaporize a hole through 1000 feet of Solid Steel in very short time.

Very short time is sort of indeterminate.

 

Now, just wild ass guessing, but if the laser could drill through a centimeter of steel, in maybe a 1/4 second burst, then would a feature writer consider two hours a 'very short time'?

[SplitInfinity]

Unsourced information is not particularly compelling. I don't what what you've heard, especially when it doesn't jibe with information that's publicly available.

 

———

 

"thus bringing a shipboard FEL closer to realization" is not what you say about a system that's ready to go on board a ship.

 

http://detroit.cbslocal.com/2012/12/11/niowave-breakthrough-advances-u-s-navy-free-electron-laser-program/

 

Being funded through ONR means it has all the hallmarks of being a research program, with several people getting funding, in order to come up with the best solution. Not something being produced, ready to deploy.

 

Also, from 1 year ago:

http://www.wired.com/dangerroom/2012/03/navy-lasers-four-years/

"Within four years, they claim they’ll have a working prototype of a laser cannon, ready to place aboard a ship."

 

A working prototype is still (at least) 3 years away, according to that. R&D rarely jumps ahead of schedule. Also, the motorboat targeting test was a 15 kW device. That's a far cry from 1 MW, or even the 100 kW mentioned as being "militarily useful"

 

When it comes to the FEL deployment...CVN-78 Gerald R. Ford and CVN-79 J.F.K. will have a limited FEL system at first. CVN-80 Enterpise is planned to have the end result design installed so yes...there will be a time lag.

 

Split Infinity

 

I think the 1000 feet in a second* is a poorly-worded blurb on the part of whomever was the public relations person. I think they were giving a rate of cutting. I doubt the navy ever wanted to give the impression they were ever thinking about cutting through super-thick targets. But the link I found above says 20 feet in 1 second for 1 MW, which is a lot more plausible. That's about a quarter inch per ms, meaning the time to zap an incoming missile is short, which is the whole point of the system — you don't want to have to hit the same spot with the laser for very long.

 

*if that's an accurate number. Thus far SplitInfinity has failed to give even a single link to supporting information for the claims, and since some claims have been demonstrably wrong I'm happy to call BS on all of the non-obvious ones, pending some kind of reference.

 

The 100o feet claim is a theoretical one given by Discover Magazine...not me...but it is possible given proper energy requirements are filled.

 

Split Infinity

 

The actual quote was

Very short time is sort of indeterminate.

 

Now, just wild ass guessing, but if the laser could drill through a centimeter of steel, in maybe a 1/4 second burst, then would a feature writer consider two hours a 'very short time'?

I posted the theoretical power requirements earlier in this post.

 

Split Infinity

[swansont]

Still no links, I see. Just a vague mention of a magazine — not even an issue number.

[John Cuthber]

The 100o feet claim is a theoretical one given by Discover Magazine...not me...but it is possible given proper energy requirements are filled.

 

Split Infinity

But it is not possible to fill those energy requirements,

As I explained earlier, even the biggest reactor in the world couldn't produce the power to make a significant sized hole that long because of radiative heat losses.

Discover magazine does talk about these and perhaps the printed copy does say something about 1000 feet of steel

http://discovermagazine.com/galleries/zen-photo/l/laser-weapon#.UWB01ZP_nTo

 

 

However the targeting is an essentially impossible task.

The laser is far too big and heavy to pick it up and point it at a target.

So you have to use mirrors to steer the beam.

That's not a problem, and nor is moving the mirrors to keep the beam pointed at the target.

The problem is that the mirrors or a window has to let the beam through and it has to be exposed to the air.

 

At those levels a spot of dust or a drop of sea spray would absorb a lot of power, it would get hot enough to ionise the air round it (and also it would heat the surface of the mirror or window).

Ionised air isn't transparent so it would absorb even more energy and get hotter and hotter.

The first scrap of dust would result in the mirror exploding.

It would be suicidal to fire it in mist, fog or rain.

 

Even clean optics have limited power handling capacity. Here's a fairly typical spec for a high grade mirror.

http://www.edmundoptics.com/optics/optical-mirrors/flat-mirrors/high-energy-argon-ion-laser-mirrors/2723

 

They handle about 1 KW /cm^2

You were talking about a 5GW beam power

So that's about 5 million cm^2 as the minimum area for this mirror.

A mirror about 8 feet across or something like that.

Now, there are telescope mirrors that big and so it's not an absurd size, but remember you have to slew it round to make up for the motion of the ship and the target.

Unfortunately that means it would bend out of shape.

 

So, this laser that you can't power would need a mirror that would be too big and heavy to steer fast enough to focus on a target that would have to be in a dust free, clean room.

 

I rather doubt that the Russians are all that frightened.

Edited April 6, 2013 by John Cuthber

[SplitInfinity]

But it is not possible to fill those energy requirements,

As I explained earlier, even the biggest reactor in the world couldn't produce the power to make a significant sized hole that long because of radiative heat losses.

Discover magazine does talk about these and perhaps the printed copy does say something about 1000 feet of steel

http://discovermagazine.com/galleries/zen-photo/l/laser-weapon#.UWB01ZP_nTo

 

 

However the targeting is an essentially impossible task.

The laser is far too big and heavy to pick it up and point it at a target.

So you have to use mirrors to steer the beam.

That's not a problem, and nor is moving the mirrors to keep the beam pointed at the target.

The problem is that the mirrors or a window has to let the beam through and it has to be exposed to the air.

 

At those levels a spot of dust or a drop of sea spray would absorb a lot of power, it would get hot enough to ionise the air round it (and also it would heat the surface of the mirror or window).

Ionised air isn't transparent so it would absorb even more energy and get hotter and hotter.

The first scrap of dust would result in the mirror exploding.

It would be suicidal to fire it in mist, fog or rain.

 

Even clean optics have limited power handling capacity. Here's a fairly typical spec for a high grade mirror.

http://www.edmundoptics.com/optics/optical-mirrors/flat-mirrors/high-energy-argon-ion-laser-mirrors/2723

 

They handle about 1 KW /cm^2

You were talking about a 5GW beam power

So that's about 5 million cm^2 as the minimum area for this mirror.

A mirror about 8 feet across or something like that.

Now, there are telescope mirrors that big and so it's not an absurd size, but remember you have to slew it round to make up for the motion of the ship and the target.

Unfortunately that means it would bend out of shape.

 

So, this laser that you can't power would need a mirror that would be too big and heavy to steer fast enough to focus on a target that would have to be in a dust free, clean room.

 

I rather doubt that the Russians are all that frightened.

 

Again...I am not the one that created the 1000 feet example.

 

As far as optics...I have stated several times that standard mirror optics would be vaporized upon contact and what will be used is Multi-Compound Prisms similar to an Insects compound eyes.

 

The heat problem is a big one but as far as I know this has been over come...I admit I have absolutely no idea how they did this.

 

When one looks at the history of High Tech. U.S. Military programs...there exists a level of information specific for the public and another specific for those involved with such programs. History has shown many times that what is public is very often no where near the reality of what is secret.

 

Split Infinity

[John Cuthber]

Whoever originally made the 1000 foot claim, you reported it and you have yet to cite the original author/ publication.

You said it was a magazine, but the on-line version doesn't mention it.

Mirrors can, in principle, be made thinner and lighter than prisms or lenses so you have just told us they made the targeting problem more difficult.

But they still have surfaces so they have not made the dust problem any easier.

So, in effect you have said they made things worse, not better.

The reasonable response to solving the heating problem is that they have not solved it.

Though this does not matter, since they don't actually have a laser that powerful.

And, if they did, they wouldn't have a power supply that could drive it.

 

In the history of military invention past experience shows one thing quite often: they lie.

 

What will it take for you to accept that you have been suckered?

[zapatos]

Here is an article on the system with a video of it in action (if you don't mind watching a commercial first).

http://www.wired.com/dangerroom/2013/04/laser-warfare-system/

[John Cuthber]

Here is an article on the system with a video of it in action (if you don't mind watching a commercial first).

http://www.wired.com/dangerroom/2013/04/laser-warfare-system/

Just for a start, that's not a FEL.

It still wouldn't work in fog, mist rain or spray.

And , outside of a clean-room, the optics would die very quickly.

It's not using all the power from a large nuclear reactor.

It's not cutting a hole through a thousand feet of steel.

And, if the Russians are familiar with colloquial English they are probably laughing even more at the name of the USS Ponce.

.

[zapatos]

Sorry, the systems are related. You need to follow the Free Electron Laser link in the article.

http://www.wired.com/dangerroom/2011/02/unexpectedly-navys-superlaser-blasts-away-a-record/

[John Cuthber]

"Right now, the free-electron laser produces a 14-kilowatt beam."

 

It still wouldn't work in fog, mist rain or spray.
And , outside of a clean-room, the optics would die very quickly.
It's not using all the power from a large nuclear reactor.
It's not cutting a hole through a thousand feet of steel.
And, if the Russians are familiar with colloquial English they are probably laughing even more at the name of the USS Ponce.

 

It's a nice toy.

Now, if they can just crank the power up a thousand times they will only be about a hundred fold short of the original claim.

Meanwhile on WIKI

"The CO2 laser can be constructed to have CW powers between milliwatts (mW) and hundreds of kilowatts (kW)"

http://en.wikipedia.org/wiki/Carbon_dioxide_laser

 

Since 8KW is "off the peg"

http://www.rofin.com/en/products/cosub2sub_lasers/

the 14KW figure doesn't look so good.

Edited April 10, 2013 by John Cuthber

[zapatos]

Yeah, I was not trying to support the OP. I just saw an article on the laser and thought it might be of interest.

[swansont]

The absorption coefficient for water is about 10^-4/cm at ~500 nm. And if we assume the fill fraction during rain or mist is 0.1 (i.e 1mm drop has 9 mm between it an the next drop along some line, on average) that means the 1/e attenuation distance is of order a kilometer. And, of course, that water will tend to flash to steam and when it does, the attenuation goes down, which you get if the beam is not tracking too quickly, and an advantage of a higher-power beam is that it will clear out the water that much faster. So really what you'd want is a window for water vapor, which is around 10^-4/m (notice a scale difference between the two graphs) at an appropriate wavelength http://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water


Then it just depends on how much water there is (i.e. I don't know if that graph is for 100% humidity at STP, or some other conditions). But that implies you might be able to "burn" a hole and have an effective range of several tens of km. So this may work just fine, range-wise, in adverse weather.

[SplitInfinity]

"Right now, the free-electron laser produces a 14-kilowatt beam."

 

It still wouldn't work in fog, mist rain or spray.

And , outside of a clean-room, the optics would die very quickly.

It's not using all the power from a large nuclear reactor.

It's not cutting a hole through a thousand feet of steel.

And, if the Russians are familiar with colloquial English they are probably laughing even more at the name of the USS Ponce.

 

It's a nice toy.

Now, if they can just crank the power up a thousand times they will only be about a hundred fold short of the original claim.

Meanwhile on WIKI

"The CO2 laser can be constructed to have CW powers between milliwatts (mW) and hundreds of kilowatts (kW)"

http://en.wikipedia.org/wiki/Carbon_dioxide_laser

 

Since 8KW is "off the peg"

http://www.rofin.com/en/products/cosub2sub_lasers/

the 14KW figure doesn't look so good.

 

I can tell you from experience that the Russians do not laugh at ANYTHING to due with U.S. High Tech. Military applicable projects...whether they come to fruition or not.

 

There is what is PUBLICLY known and what is PRIVATELY known.

 

As example...Lockheed was working on and testing the Have Blue program from which came the F-117...many, many years before anyone...including the Soviets even considered such a program was in such late stages. The precurser to the Have Blue program originated with the R version and then SR-71 program...as that aircraft of which some of it's design originated IN THE LATE 1950'S...used Aircraft Geometry and Radar absorbant Paint to be Stealthy.

 

When Reagan and Gorbachav met in the 80's to discuss Arms Reduction...the Soviet Military made it absolutely clear that the Soviet Leader WAS NOT to sign any reduction agreement unless Reagan shelved the SDI or Star Wars initiative even though this program was not even off the ground.

 

I have many friends in the U.S. Military as well as I am associated to certain companies specific to Defense and all these people will tell you...The number 1 worry of Russia today is that the U.S. will develop and deploy a High Tech. Missile Defense Shield using a combination of the FEL and the SM-3 ABM/ASAT.

 

It was DECADES before anyone knew about the SR-71 and the F-117 was flying missions directly over Eastern Europe on the Soviet Side without ANYONE knowing about it.

 

The U.S. Military and CIA has not disclosed what the replacement was for the SR-71 and you all can be certain that THERE IS a replacement flying and has so for some time.

 

So when I read posts here laughing off the possible abilities and apps for the FEL...I am the one laughing.

 

Split Infinity

[John Cuthber]

Stealth weapons are made by applying known technology.

Making a beam that travels through dusty, misty air and optics isn't.

 

Swansont's analysis doesn't inlcude the self focussing effect (or the simple focussing effect of raindrops) or the effect of less volatile strong absorbers like dust.

 

Once they get hot, they ionise the air round them and then that air is opaque.

 

You can hide an air craft (especially a stealth plane- that's the point).

Ye' cannae change the laws of physics.

 

 

Incidentally, re "It was DECADES before anyone knew about the SR-71 and the F-117 was flying missions directly over Eastern Europe on the Soviet Side without ANYONE knowing about it."

Unless you are a senior member of the Russian intelligence service, there's no way on God's earth that you can know if that statement is true.

 

Why did you post it on a science site?

Edited April 11, 2013 by John Cuthber

[swansont]

!

Moderator Note

Posts having nothing at all to do with politics or a free electron laser on a ship have ben split off http://www.scienceforums.net/topic/74375-big-bang-and-changing-laws-of-physics/