Scientists Use Laser to Redirect LIghtning Bolts!

Lightning safety is something that scientists continually work on, not only for airlines, but people on the ground. Every year around the world there are a good number of lightning deaths. Lightning rods have been around for a couple of hundred years. Scientists have been researching using laser beams to open "channels" for lightning to follow, and they recently had some success, although it's expensive. Here's the research.

(photo: Using this high-powered laser on a mountain in Switzerland, physicists have finally created a guide light for lightning.TRUMPF/MARTIN STOLLBERG)

Scientists use a laser beam to control lightning bolts 

SCIENCE Magazine, Jan 16, 2023

Researchers successfully diverted lightning using a high-powered laser in the first demonstration of the technique outside a laboratory. Scientists believe the technology could eventually help control lightning strikes around airports and launchpads while potentially reducing the thousands of fatalities and $3B in damages each year resulting from the phenomenon.

THE LASER BEAM TEST Traditional metal lightning rods only cover an area as wide as the rod is tall, limiting their application on large sites. To test covering a wider area, the researchers created a virtual lightning rod using a laser pulsing 1,000 times per second near a 400-foot tower in Switzerland. During storms in the summer of 2021, the laser's rapid beams heated a path of charged air near the tower, ultimately steering four lightning strikes through the ionized channel over six hours (see images). Read how it works here.

LIGHTNING OCCURS Lightning occurs when static electricity builds up in storm clouds and begins to break down the surrounding air molecules. Paths of electrically weakened air spread like cracks in a car windshield. Once one such path reaches something on the ground or connects with other paths climbing from the surface, 30,000 amps of current gush through the jagged channel in a massive discharge that can blast a hole in a building and set it ablaze.

HOW A LIGHTNING ROD WORKS To help prevent such damage, people rely on a technology invented in 1752 by American polymath Benjamin Franklin: the lightning rod. Consisting of a pointed metal rod attached to a building’s roof and connected to the ground by a wire, the rod creates a strong electric field that draws lightning away from the building. When the rod is hit, the wire safely ushers current to the ground.

HOW THE LASER WOULD WORK The laser light ionizes some air, which then works like a lens to further focus the light into a long “filament” the width of a hair. The thin beam heats the air, driving away molecules and leaving a channel of lower density air, which better conducts electricity.It works at least in laboratory experiments.

TRIALS Efforts to control natural lightning in New Mexico in 2004 and Singapore in 2011 still failed to influence the paths of bolts. Now, scientists have succeeded. They placed a femtosecond laser atop Säntis mountain in northeastern Switzerland next to a 124-meter-tall telecommunications tower. Like a giant lightning rod, the tower gets hit with lightning more than 100 times a year. The researchers shined their laser past the top of the tower from July to September 2021 during a total of more than 6 hours of thunderstorms.

SUCCESS IN SWITZERLAND In all four lightning strikes taken with the laser on, the lightning followed the path of the laser beam before jumping to the tower, the 28-member team reports today in Nature Photonics. Thus, researchers steered about the last 50 meters of each bolt’s otherwise random trajectory. The result is the culmination of a 5-year, €4 million European project.

A LOT TO PUT IT TOGETHER - AND IT IS EXPENSIVE To make it work, researchers had to disassemble their delicate laser, take it up the mountain piece by piece in a gondola, and enlist Switzerland’s biggest helicopter to assemble a building to house it. But can a $2 million laser compete with a dirt-cheap lightning rod?