Few things are more impressive than a lighting strike. Lightning can carry millions of volts and while it can be amazing to watch, it is somewhat less amazing to be hit by lightning. Rockets and antennas often have complex lightning protection systems to try to coax the electricity to avoid striking where you don’t want it. However, a European consortium has announced they’ve used a very strong laser to redirect lightning in Switzerland. You can see a video below, but you might want to turn on the English closed captions.
Lightning accounts for as many as 24,000 deaths a year worldwide and untold amounts of property and equipment damage. Traditionally, your best bet for protection was not to be the tallest thing around. If the tallest thing around is a pointy metal rod in the ground, that’s even better. But this new technique could guide lightning to a specific ground point to have it avoid causing problems. Since lightning rods protect a circular area roughly the radius of their height, having a laser that can redirect beams to the area of a lightning rod would allow shorter rods to protect larger areas.
The idea is simple. Electricity follows a path of least resistance. When electric charges are high enough to cause the air to ionize, that creates lightning. However, if a laser ionizes the air preemptively, the lightning will be prone to follow that path instead of creating a new one.
You won’t be able to replicate this with your favorite laser pointer. The laser used is a 1 kW laser that puts out a one picosecond pulse. A Swiss radio tower at a height of over 2.5 km was monitored for lightning strikes both with and without the laser system. The increased protection was modest, only 60 meters more than the lightning rod alone. However, the team wants to shoot for a 500-meter increase.
We don’t know if this will be super practical for most lightning protection jobs. We doubt that even [styropyro’s] laser is up to the task. If you want more background on the natural phenomena, [Maya Posch] took us through it last year.
Lighting -> lightning
I think that’s what you mean in the title and first sentence… And in a few more sentences.
Must have been the lightning strike on my computer that ate all the extra letters.
Back to the training data for some refinements…
AI Williams is getting better every time we run the training data…
Lots of refinements.
https://www.engadget.com/cnet-reviewing-ai-written-articles-serious-errors-113041405.html
When >1kW Q-switched picosecond lasers will be as cheap as a metal rod, we will see this technology everywhere, I cannot wait !
Please don’t buy one unless you know what you’re doing (the safety gear will cost more than the laser) but an aliexpress hair removal laser is this powerful and costs about as much as the copper needed for a tall structure.
https://www.weather.gov/safety/lightning-odds
With <50 fatalities in the US, I find 24k fatalities/year worldwide an unbelievably high number.
It doens’t check out with plain math, but then I don’t find it that surprising: All it takes is an outdoor concert in a 3rd world country and people not to evacuate it and you can zap 100 or 1000 people at once. I don’t know how far the cone of energy propagates around the center of impact to be fatal. There are calculations for distance and it depends how far your feet are apart.
Safety in the USA may be higher than in densely populated India. No offense, India is doing great in many things. They rolled out tapwater from 17% to 44% of all people in just 3 years. Consider how many live rural. The ones in large cities can be easily at danger of lightning as well.
This report refers to the source of the number:
https://www.researchgate.net/publication/267855823_Annual_rates_of_lightning_fatalities_by_country
You can download the PDF of the report here:
https://www.researchgate.net/profile/Ronald-Holle/publication/267855823_Annual_rates_of_lightning_fatalities_by_country/links/54af154a0cf29661a3d49861/Annual-rates-of-lightning-fatalities-by-country.pdf
I can’t find a copy of the original paper that came up with the 24000.
24000 appears to be an estimate based on an assumed rate of six lightning fatalities per million people in developing countries. There appears to be little hard data for most such countries, so the report uses historical rates from other countries with (more) complete records.
Well, there are 200+ more countries than the US in the world, so you can run the numbers. Also It doesn’t strike only 3rd world countries (as implied in another comment).
US is about 5% of the world population, so 47/5%=940. I can’t believe US has a 1/25th fatal lightning strike risk compared to the world average.
Historically, the US had a rate of about 6 lightning deaths per year per million inhabitants. That’s before lightning rods and modern improvements (before 1900.)
The US currently has a rate of lightning deaths of 0.3 per years per million inhabitants.
That’s a factor of 20.
The figure of 24000 is an estimate based on world population and that historical value of 6 per million per year. The papers I linked to mention that it is hard to impossible to get accurate values for deaths per year due to lightning, hence the use of the historical rate to make an average.
If you simply applied that 6 per year per million people, you’d come up with over 47000 per year for the current world population (7 888 000 000.) Since the papers mention 24000, it seems they only applied the estimate to countries with no usable numbers.
I was also suspicious. Google first result reports 6000-24000 so consider 24k the upper limit estimate. Agree though that reporting maximum estimate is a little misleading but… even 6000 per year is kind of a lot!
I don’t understand, the laser is only a kilowatt, but it worked for 1 picosecond, or the laser consumed 1 kilowatt of power in 1 picosecond
The Alculation is off. It’s 1e+12 watts, or 1 terawatt pulse according to paper
that’s a killowatt on average, fireing 1picosecond pulse but there’s no mention of the repeat rate… without knowing if it’s fired once per second, minute, or even hours means you can’t really get a sense of the pulse energy, but the paper also mention 1 joule per 1picosecond pulse, which actually means something… like dan said
I was going to suggest that this could be the front end for a lightning energy harvesting system, as getting the lightning to hit your power harvesting system has traditionally been one of the really difficult things about the project. It looks like a German company called Teramobile is already trying this with ultrafast lasers to produce ionized columns for initiating lightning strikes.
I’m imagining dumping the power into a million liters of metal salts in a big vat that serve as a massive resistor capable of absorbing a gigajoule of energy and converting it to heat, then extracting that through a Rankine cycle system.
Though even in places with just crazy amounts of lightning… it’s still not very much lightning. 200 strikes per square kilometer per year is approximately the most in the world, so even if you could collect everything in from a circle a couple of km in diameter you’d still only get a dozen strikes a night into your system. 30GJ/night is, like, what, 100kW/h? I mean, not negligible, but not worth putting a lot of work into, especially as the laser’s going to suck up a lot of power itself.
@elwing The video says that 10 times a sec was too slow since the air molecules re-bound and stop being a plasma, so they created this new laser, so we know it’s at least noticeably more than 10 times a sec.
From their site:
“TRUMPF Scientific Lasers is the only company that has the expertise and technology to develop a 1 J pulse energy, 1 kHz repetition rate, 1 TW peak power laser system that is needed for carrying out the experiments within the framework of this proposal.”
Protecting critical assets against direct strikes is a great idea! That’s why we’ve been doing just that for over 50 years – visit http://www.lightningprotection.com