Scientists used a laser beam to bend a bolt of lightning for the first time
Houard, A., Walch, P., Produit, T. et al. Nat. Photon (2023). https://ift.tt/dvMxnBZ. CC-BY 4.0
- For the first time, scientists were able to show they can bend lightning from a storm with a laser.
- The project, 20 years in the making, required a super powerful laser to be shot into the sky.
- The hope is the laser could draw lightning away from places we don't want it to hit.
Researchers were able to deflect lightning using a powerful laser shot into the sky — a scientific first.
A powerful laser was able to deflect a lightning bolt almost 200 feet before it hit a lightning rod, greatly improving the rod's function.
The findings, published in January, show that lasers could one day be used as protection against dangerous thunderstorms, which kill an average of 43 people in the US every year and cost US homeowners almost $1 billion in insurance claims in 2022.
Source: TRUMPF group
Lasers as lightning rods
The idea to use a lasers lightning rod goes back to the early 70s, said Aurélien Houard, a research scientist in the Laboratoire d'Optique Appliquée at Swiss university EPFL and coordinator of the project, in a blog post on French site Polytechnique Insights.
The principle is simple: laser beams, if they are powerful enough, can heat the air so intensely that they trigger molecules to release their electrons.
This creates a channel full of charged electrons along the laser beam — and all those electrons attract lightning bolts, which seek the path of least resistance between the clouds and the ground.
Source: TRUMPF group
The problem is that this channel is very short-lived, and laser beams flicker. Though scientists had been able to deflect lightning in the lab, they'd never been able to do it in real-life conditions.
To make sure the channel stayed open long enough to bend lightning during a storm, scientists developed a laser able to fire high-powered pulses 1,000 times per second.
That was a joint effort by the University of Geneva (UNIGE) and EPFL in Switzerland, the École Polytechnique in France, and TRUMPF scientific lasers firm in Germany.
Their laser pulsed 100 times faster than their previous laser, which means the laser is "100 times more likely to catch lightning," Houard said per The Wall Street Journal.
Testing the laser at the top of a Swiss mountain
To test the new gear, the scientists brought their 3-ton laser to the top of the 8,000-foot-high Mount Säntis in Switzerland. The advantage of this location is its 400-foot communications tower, which is reliably hit by lightning at least 100 times per year.
The laser was powered up any time the weather forecast predicted thunderstorms.
Eventually, the scientists were able to record a natural lightning bolt that, for the first time, followed the laser beam before hitting the tower.
"Of course, we needed to analyze a lot more data following this," said Jean-Pierre Wolf, professor of applied physics at UNIGE, said in a video accompanying the findings in French.
"But that picture spoke a thousand words, there was no doubt possible. When I saw this picture, I knew we had it," he said.
Houard, A., Walch, P., Produit, T. et al. Nat. Photon (2023). https://ift.tt/dvMxnBZ. CC-BY 4.0
Lightning-protection gear needs an upgrade
The finding provides hope that lasers could one day offer a much-needed new avenue for protection against lightning bolts.
Lightning rods, which were invented by Benjamin Franklin, remain the best form of protection we've got against lightning, per a press release accompanying the findings.
The problem is that their protection extends only as far as the rod is tall. That means a 10-foot tall rod will protect anyone within 10 feet of the pole, but not any further than that, per the press release.
A laser, on the other hand, could reach high in the clouds.
"We found that the discharge could follow the beam for nearly 60 meters (196 feet) before reaching the tower," Wolf said, per CNN.
That meant that the laser "increased the radius of the protection surface from 120 meters (393 feet) to 180 meters (590 feet)."
The next step is to try to develop a laser that can reach even higher up in the sky.
That is possible in theory. Houart cautioned, however, that this technology is likely at least ten years away from being polished enough to reach the market, The Wall Street Journal reported.
The findings were published in the peer-reviewed journal Nature Photonics on January 16.
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