A team of researchers from the University of Geneva installed a huge laser atop a mountain to shoot it at the sky, and act as a high-tech lightning rod.
The team is led by Jean-Pierre Wolf, a Swiss physicist who’s been working with laser for more than 20 years and has been particularly fascinated with attempting to control the weather with it.
Laser creates very narrow, high-energy beams of light. Its applications range from cutting diamonds to surgery to reading barcodes, and Wolf believes he can add another to the list: protecting us from lightning.
Wolf’s leading an EU-funded consortium which includes universities in Paris and Lausanne, as well as rocket manufacturer Ariane Group and the maker of the laser, German high-tech company Trumpf.
After a year of delays due to the pandemic, the laser has been transported to the summit of Säntis, a mountain in the Swiss alps with an elevation of 2,500 meters.
“This is one of the places in Europe that’s struck by lightning the most,” explained Wolf. “There is a radio transmission tower there which gets struck 100 to 400 times a year. So it’s an ideal place to make our proof-of-concept experiments.”
Lightning begins when winds inside the cloud become very turbulent. Water droplets in the bottom part of the cloud are caught in the updrafts and lifted to great heights where the much colder atmosphere freezes them.
Meanwhile, downdrafts in the cloud push ice and hail down from the top of the cloud. Where the ice going down meets the water coming up, this creates seperate zones with opposite charge.
These electric fields can become very strong, and because opposite charges attract, they can connect through a discharge of electricity — which we call lightning.
The laser rod would help the clouds discharge lightning in a controlled way. “That’s why we call it a laser lightning rod,” said Wolf.
The beam will run alongside the existing transmission tower — about 120 meters tall.
Traditional lightning rods are only able to protect a limited area on the ground, no matter how high they are built. Wolf hopes that the laser, however, will help protect a larger area on the ground, although he can’t yet say how much larger.
The theory is that the laser can act both as a lightning rod, catching bolts that would strike anyway, and also trigger extra ones.
“That would mean we would be unloading the thundercloud, reducing its voltage and then preventing further lightning strikes in the surrounding area,” said Wolf.
Wolf says that the most immediate practical applications of the technology would be to protect rockets such as those carrying satellites into orbit during launches, and at airports, where it could be turned on during storms.
The laser shoots 1,000 times per second and it’s so powerful that “a single pulse at peak power is equal to that produced by all the nuclear power plants in the world,” according to Wolf.
For safety reasons, a five-kilometer wide no-fly zone will be in place when the laser is active. Although it poses no risk to aircraft, laser is harmful to human eyes when looking directly at the source.
The laser won’t be switched on all the time, but rather only when increased lightning activity is detected.
Tests will last until September, the end of lightning season. If they are successful, the next experiment could be at an airport, Wolf said.