Scientists say it’s the first time they’ve used a laser beam to guide lightning, hoping the technique will help fend off deadly arrows and perhaps even make them work one day. Lightning strikes around the earth 40-120 times per second, causing more than 4,000 deaths and billions of dollars in damage each year.
But the main protection against such lightning from above remains a modest lightning rod, which was first invented in 1749 by the American scholar Benjamin Franklin. A team of scientists from six research institutions has been working for years to use the same idea, but replacing the simple metal support with a much more sophisticated and precise laser. In a study now published in the journal Nature PhotonicsThey describe using a laser beam shot from the top of a Swiss mountain to direct lightning 50 meters away.
“We wanted to show for the first time that a laser can affect lightning and control it in the easiest way,” said Aurelien Houar, physicist at the ENSTA Institute Applied Optics Laboratory in Paris and lead author of the study. But “it would be even better if we could trigger lightning” for future applications, Howard told AFP.
how to catch lightning
Lightning is a discharge of static electricity that builds up in storm clouds or between clouds and the ground. The laser beam creates a plasma in which charged ions and electrons heat the air. A laser on the top of a Swiss mountain that manages to direct the lightning 50 meters. The air has become “partially conductive and therefore the preferred route for lightning,” Guard said.
When scientists tested this theory earlier in 2004 in New Mexico, their laser did not detect lightning. This laser failed because it didn’t emit enough pulses per second for lightning, which took milliseconds to produce, Howard said.
He added that “predicting where lightning will strike” is also difficult. For the final experiment, the scientists left little to chance. They shot a car-sized laser that could emit up to a thousand light pulses per second at the 2,500-foot summit of Mount Santis, northeast of Santis.
At the top is a communications tower, which is struck by lightning about 100 times a year. Two years after building the powerful laser, it took several weeks to move it piece by piece by cable car. Finally, the helicopter would drop large containers to house the telescope. The telescope focused the laser beam at a maximum intensity of about 150 meters in the air, just above the top of the 124-meter tower. The beam is initially 20 centimeters in diameter, but tapers to only a few centimeters at the apex.
lightning saddle
During a storm in the summer of 2021, scientists were able to photograph its rays moving lightning around 50 meters. Interferometric measurements showed that the other three shocks were also directed. Most lightning originates from ancestors in the clouds, but some can also come from the ground if the electric field is strong enough.
“The current and power of lightning really becomes clear when the ground meets the cloud,” Howard said. The laser targets one of these predecessors, making it “much faster and flatter than the others.” “Then it will connect to the cloud before it burns out.”
This means that theoretically this technique could be used not only to repel lightning, but also to activate it. This could allow scientists to better protect strategic facilities such as airports or missile launch sites by attacking at a time they choose. In practice, this will require the high conductivity of laser plasma, which scientists believe they have yet to master.
Source: Port Altele
