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Curved Laser Beams Could Help Tame Lightning
Urchin writes "Laser beams just gained a new property — they can curve through space. That's what happens when ultrashort laser pulses pass through a phase pattern mask and a lens, which together shift the most intense region of the beam from the center to the right-hand side. The asymmetry in the pulse causes it to drift progressively further to the right along an arc as it travels. The laser beam is so intense that it ionizes the air it passes through to create a curved plasma channel. Those kinds of channels can be up to 100 meters long — direct them at thunderclouds and they could first trigger lightning to spark and then act as a convenient but short-lived lightning rod to guide it safely to the ground, according to some researchers."
"Yeah, curving lasers, very viable".
"Lasers shoot straight, stupid!"
"So this beam is some kind of plasma or what? Laser? Are you kidding?"
Now they will all see! My sharks will be able to shoot lasers from behind a corner!
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So, this is a neat twist on an older idea.
I can't really imagine a practical use for this (a lightning rod seems like a much cheaper solution) but it's pretty nifty science.
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just gained a new property
wait, what? I don't think that's how science works...
What's the value of information that you don't know?
Igor, fire the lasers!
People replying to my sig annoy me. That's why I change it all the time.
This looks like a clever anti shark plot to me. Eventually the curved beam will go all the way around and kill the shark itself. No thanks, I'm sticking to straight shooting lasers on my sharks. Nice try, Austin.
Negative moral value of force outweighs the positive value of good intentions.
The lightening rod is just for silly editors. If the idea works, it is a thundercloud discharger, grounding it. The idea being that it would stop strikes where you don't want them.
A lightening rod works after the fact and only on a very small area.
Say a thundercloud approaches, you can A: have lots of very tall spikes penetrate it so it discharges. B: create a grounding effect with some kind of plasma arc or C: put lightening rods all along the storms path hoping that the thunder will hit the rod, not something else.
So no, lightening rods are not an alternative in the same way that crash barriers are not an alternative to safe driving or safety belts.
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You may solo them, I prefer them in a group.
We've already seen bent lasers since 2000 ;)
I think we can keep recursing like this until someone returns 1
Could this also be used to initiate a set of conducting paths for tasers? That would increase their range quite a bit...
From the coverage in cited New Scientist article, it isn't clear that curved laser beams have any advantage in triggering lightning over straight beams. As it is said, it would be fun to see that curved lightning. Sounds rather like pure fun, no big scientific breakthrough, as it comes to atmosphere control.
"they can curve through space"
Errr...no...
" The laser beam is so intense that it ionizes the air..."
Do I need to point out the obvious incompatibility between the two statements?
This is what high energy "space war" lasers--or more precisely the beam aiming/focusing systems--have been fighting with for a long time when dealing with the atmosphere. Send a very high powered beam through the atmosphere... You get ionization and heating. The center of the beam heats/ionizes more rapidly. That causes defocusing or "thermal bloom". Air (wind) traveling through the beam has a greater distance to travel through the center of the beam than at the edges, resulting in greater heating/ionization, the resulting change in density across the beam surface causes the beam to bend.
You've basically got hold of one end of a string--looking down a beam path that's constantly wiggling around--and constantly trying to correct for the intervening atmospheric effects to keep the beam on target by manipulating one end of a string. Which is why we still don't have effective anti-missile laser systems.
That said, for the purposes descibed in TFA, this should be much simpler and much more feasible.
Those are obviously blasts of concentrated energon, not lasers. As such, they move slowly and in discrete units. As an added bonus they're easier to draw.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
Direct them at tasers and they could first trigger lightning to spark and then act as a convenient but short-lived lightning rod to guide it safely to the ground, according to some researchers."
If a laser could intercept the dart before it hits you ... I can just see it now - instead of tin-foil hats, geeks will be wearing their anti-taser laser phasers.
The failure of the first particle beam/laser hybrid was due to the particles deviated from target because of their mass, falling out of the laser's beam.
So that's fixed now?
kulakovich
i guess he was thinking about conservation of energy and momentum? shooting something with momentum (yes, light has momentum) should make it go in a straight line, not a curved one, unless other forces are also involved, like in refraction by the atmosphere for example. In space, no atmosphere, so maybe no curved lasers?
Normally the refractive index of a material is quoted as a constant. However, light radiation will slightly distort the electron levels of the material they are passing through, and this will have effect the refractive index. Normally this effect is very tiny. However, if you design high-power lasers, then it can become a nuisance. If you have a bright spot to your beam, then this will locally raise the refractive index. This will, in turn, cause the light to come to a line focus, which raises the intensity even more. If you do not design high-power optics to account for this, then a flat, uniform beam of light can spontaneously divide into a set of filamentary hot spots, which can smash your expensive optics.
There is another process, more usually associated with high-power ion beams. An ion beam that travels a long distance in air can twist like a garden hose squirting water. The ion beam heats up the air it is passing through, which creates a kind of pipe through the air as the hot atoms move away. This is a nuisance if you want to make the beam go in a straight line. One way of keeping an ion-beam weapon firing straight is to put a laser pre-pulse to heat a straight line through the air for the ion beam to travel down.
How fast can it cook 2000 pounds of Jiffy-pop?
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Christodoulides's team's work could be combined with his to help aim the laser pulses and plasma channels at specific targets, such as clouds, although he points out that the laser pulses can also be guided using mirrors. "But it would be fun to see curved lightning discharges," he says.
This article is cool up until the lightning bit. As the quote from TFA shows, there's absolutely no connection between the curved lasers and the technique for triggering lighting. As far as generating an ion channel goes, the curved laser does nothing a straight laser can't. The only connection between the otherwise completely disconnected bits of research is that the lightning guy commented on the curved laser stuff and essentially said that while using mirrors is more feasible in his project, using curved lasers would look cool.
Everytime someone comes up with an interesting discovery in science, people invariably ask what it's good for. Ditto for math. The problem is that a lot (most?) research is done for its own sake, to discover new things, rather than having any particular application in mind. History has shown that applications tend to come later, and in the places you least expect it, so it pays to just be curious. People thought group theory was just weird abstract shit until someone figured out how to use it in applied chemistry.
It's said when the need to immediately justify every new discovery has gotten to the point where an article needs to include a completely contrived and ridiculous application just to placate people.
I would like to point out that the original 'Frankenstein' novel by Mary Shelley makes no statement connecting a lightning strike with animation of Dr. Frankenstein's golem. There is reference to a lightning striking a tree during his youth, and his amazement at natures power, but that is all.
They just put so many photons into their laser blasts that the blasts can't move that fast anymore. In fact, if they'd put any more photons in, air friction would cause the blasts to burn up before they reach their target.
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Personally, I won't be impressed unless I see light bend through space-time. THAT would be a feat!
Meh. I already saw that next year.
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I don't really care about Austin powers. I surprised no on brought up the prospect of dressing up like an undead mage and calling lightning around you when there's a storm. How cool would that be? Now to make Molotov Cocktails that explode like arcane magic.
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Would shooting a 3100 meter grounded cable into a lightning cloud actually discharge it into the ground?
If so, why indeed are we messing with these lasers at all? Why don't we tap lightning clouds reliably for power that way?
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I used to work on this technology. The justification for it is really simple. If you could prevent just one lightning induced internet or power outage the amount of money saved would more than pay for all the research to date.
Under conditions When it works these systems are more effective than lightning rods. But to make these things ubiquitously functional and dependable is not a simple matter.
The airy beam decribed here I believe is just a variation of the old axiconic focus concept. With an axicon the beam only "looks like" it is bending. But the light does not bend per se. What is happeing is that one creates a fresnel lens and adjusts each lens segment to focus at a different foci. If you do this densly enhough the foci merge into a line. the light passing through one foci immediately diverges and does not pass through the next focii. That next focii is formed by diffenent rays. But to the viewer it looks like a continuous filament.
This is distict from soliton filmamentation. In this kind of filmentation the light realy does self-induce a light guide that allows an extended filemanet like focus. It's not unreasonable to imagine that a clever person could design an assymetric filament that would propagate it's light guide into an arc.
The description of the system uses language draw from both genre's of filament production, so it's not really clear which they are doing. This is understandable since due to the destructive nature of the filaments it's really really hard to insert monitoring equipment into the beam to actually determine which way the light is propagating. In many cases it's likely a little bit of both. some self containment fed by some axiconic focusing to replenish the beam as it loses energy.
In any cast the end result is a conduction channel.
Like lightning rods sometimes the purpose of the conduction channel is not to seed a lighting path but rather to cause conduction to drain the charge separation that is creating the conditions for lighting. indeed originally lightning rods were placed in large arrays to deplete the stored energy and prevent lightining rather than be sacrificial guides that preferentially attract lightning.
While either technique is good at preventing lightings lethal effects of causing fires. with electronics it is better to just never have lightining bolt at all, as our electronic systems fon't do well when the ground plane suddenly surges to a million volts.
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