If I remember my physics classes correctly, this is a surprisingly easy phenomenon to understand.
1. Lasers heat things up. In this case, they're heating up air.
2. Hot air has lower-resistance than cool air. This is why lightning happens at all: as lightning goes through its path, it heats up the air hotter-and-hotter, which allows for more and more electricity to flow. That is, lightning itself heats up the air which makes the lightning more powerful.
3. This article talks about a device that uses lasers to heat up air ahead-of-time, where you heat up the air along pre-designated "safe" paths to provide a virtual lightning rod composed of this narrow stream of hot air... rather than a metal rod.
Charging up a battery requires a lot of _energy_. Lightning doesn't have much energy.
Exploding something requires a lot of _power_. Lightning is very, very high power.
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So a dam collapsing demonstrates energy vs power, for example. The floodwaters race across the land slowly, having a small amount of power. But the floodwaters move for hours-and-hours, days and days, maybe a week or longer. That's energy, the ability to move for a long-long time.
Lightning is the opposite. Its an explosive amount of power, but it only lasts for a fraction of a second. Its so short that there's barely any energy involved.
A power-plant (and a battery) needs both. Which is where things get tricky.
Apparently you can ionize water with a laser. In theory you could float something on the surface of the ocean with an upward laser to collect lightning and a downward laser to direct it to, oh, undersea cables or submarines or whatever. Then you'd just need to miniaturize it all enough to be mounted on a shark...
Applied Energetics tried to sell a weaponized electrolaser as a sort of medium-range taser, right around 1st Fallujah, when things were really going into the thunder pot with great brown velocity[1]. I don't think they really had a working product in terms of "thing you can predictably make and which works most of the time". The idea itself is extremely compelling as a Less Than Lethal technology, though, and I'm always sort of curious why it hasn't been re-approached with newer laser tech.
[1] The whole Iraq adventure was a pointless slurry, but I remember 2004 was when even the Rah Rah people finally quieted the hell down. It seemed like that was when every military unit in theatre was panic buying whatever wacky technology they could find.
I wonder where 'pointless slurry' is meant on the scale of justifications or rationalizations of war? Maybe more favorably than 'quagmire' but less than 'good shoot'?
> I wonder where 'pointless slurry' is meant on the scale of justifications or rationalizations of war?
“pointless” = “without decent justification/rationalization", AFAICT, and “slurry” is about conditions, not justification.
> Maybe more favorably than 'quagmire'
“Slurry” seems to indicate a similar assessment of condition to “quagmire”, but maybe with less implication of stickiness? “Quagmire” doesn’t seem to be address justification, its orthogonal.
there's something odd about that article, certainly the incompetent discussion of it on here.
first of all the point is not that the laser heats up the air but that it ionizes the molecules of the air. this ionization then naturally causes a dipolar arrangement along "filaments" which then channel the flash.
lightning bolts don't strike down onto the earth out of nowhere - they are prepared by filaments growing up from the earth and down from the cloud and then a discharge happens when those filaments meet or get close enough.
I hope this means we can improve our study of lightening, it's a very exotic phenomenon. When you're first starting out studying plasma physics, you make some assumptions that make it easier to work the math, things like EM fields matter more than collisions do, it's generally low density, it's cold, it's relatively steady state. None of these things apply to lightening, an even so energetic and intense it makes antimatter[0] in our very own atmosphere. Obviously we've been able to study it, but if we can aim it we can use much more focused, higher resolution instruments.
The Langmuir Laboratory uses small rockets trailing wires to induce lightning for easier observation. It's a really fascinating process to see... a laser solution would be easier but I suspect the capital cost would take a long time to break even with the rockets.
I am a private pilot (training for instrument rating) so I believe I can help answer the first question.
Lightning is typically not the biggest problem with flying through thunderstorms. To my knowledge, it is the wind shear[1] that is most dangerous. There's also icing and hail that you may have to worry about.
Kinda reminds me of Unreal Tournament's lightning gun, except they use a proton beam instead of a laser to guide the lightning bolt:
> "The Lightning Gun is a high-power energy rifle capable of ablating even the heaviest carapace armor. Acquisition of a target at long range requires a steady hand, but the anti-jitter effect of the optical system reduces the weapon's learning curve significantly. Once the target has been acquired, the operator depresses the trigger, painting a proton "patch" on the target. Milliseconds later the rifle emits a high voltage arc of electricity, which seeks out the charge differential and annihilates the target."
Lightning is sky to ground, so weaponization is definitely in the cards. Lasers themselves are line of sight, so a ground based laser can only be used against ab aerial target, and an airborne laser will always be far weaker than a lightning bolt.
Pretty cool being able to direct lightning like this. For extra points, use the lightning to charge the laser.
But thinking about it, doesn't a large area like an airport just have several lightning rods? Seems a heck of a lot simpler in terms of operation and maintenance than a laser.
I was thinking maybe it could be helpful in the instance of forest fires. Might be able to direct lightning to areas that have been deliberately deforested/fire mitigation is in place?
My understanding is that a lightning rod can only protect a maximal radius of 60m (see https://what-if.xkcd.com/16/). This would mean a mximal distance of 120m between rods in the areas you want to protect completely. I can imagine this is difficult, in particular if the rods need to be so high that they need support cables to avoid falling at the first wind gust.
I would expect that modern airports already offer the maximal protection attainable with lightning rods. Any parts of the airport currently not protected probably does not make sense to protect with this technology.
If we can predict lightning in an area, can this lead to an alternate source of energy? What are the contextual, technical difficulties for implementing such a system?
The problem is that the energy in lightning is contained in a very short period of time, only a few microseconds. Further, to obtain that 1 million joules, one would have to handle a voltage of several million volts.
But even at 1 million joules, the typical lightning strike contains only about ¼ of a kilowatt-hour of power, which is not enough to make much difference on our electric bill.
I think the problem is you'd have to put the laser system on the area you want destroyed. Lightning can really only kill someone or light stuff on fire - and we already have weapons that can achieve this more easily that mounting a laser system in person. So it doesn't look like this is really forming an effective weapon unless you can direct the lightning, ideally stealthily, to a third location. Maybe it could be mounted to a drone that flies over? I'm still having a hard time imagining a scenario where this provides new leverage.
No, there isn't enough lightning. Global lightning output is around 1% (or less) of global energy consumption. There is nothing about the technology that unlocks lightning bolt harvesting as a new feasible power source. We could do really similar things with simple lightning rods that have been around for centuries.
I think many people over-estimate how much energy exists in a bolt of lightning. They're incredibly powerful because they transfer the energy in a millisecond or less, but there are only about a billion joules in an average lightning strike. For reference, that means you would need to get your home lightning collector struck by lightning at least once a week in order to satisfy your home energy needs.
Also, an important component in lightning is an upward convective current bringing warm and cooler air together, which cloud seeding would not affect. Clouds or rainclouds themselves don't cause lightning, which is why not all clouds/raincloud types are associated with lightning.
Nitrogen fixation maybe? Lightning breaks N2 so it bonds with O2 into NO2. Rain then brings it to the soil to be taken up by plants. But lightning does this at a much smaller scale than microorganisms do, so maybe not too important.
1. Lasers heat things up. In this case, they're heating up air.
2. Hot air has lower-resistance than cool air. This is why lightning happens at all: as lightning goes through its path, it heats up the air hotter-and-hotter, which allows for more and more electricity to flow. That is, lightning itself heats up the air which makes the lightning more powerful.
3. This article talks about a device that uses lasers to heat up air ahead-of-time, where you heat up the air along pre-designated "safe" paths to provide a virtual lightning rod composed of this narrow stream of hot air... rather than a metal rod.