Demystifying science | guide the lightning

Each week, our journalist answers scientific questions from readers.

In a word: no. But researchers are working on lasers that could attract lightning to less dangerous places, or even “unload” clouds that could create thunderstorms.

“A lightning rod can, at most, protect a few tens of meters around”, explains Aurélien Houard, physicist at the École polytechnique in Paris, who presented the first success of redirecting lightning using lasers, in January, in the journal Nature Photonics. “With lasers, we can protect within a radius of one kilometer. »

Could this technology protect forests? “At first glance, we will rather protect major infrastructures – an airport, for example. It’s a cost issue. But there are people who are working on the use of drones with a laser [pour rediriger des éclairs]. One can imagine that one could create lightning above areas less at risk of fires with this approach. »

Houard’s experiment was done in 2021 at Mount Säntis, east of Zurich, Switzerland. It took two and a half months to accumulate enough data to declare victory.

Mr. Houard’s team had made a similar attempt in 2004 in New Mexico, then in 2017 in Switzerland. In both cases it had been unsuccessful.

“Since then, we have had much more powerful laser sources,” says the Parisian physicist. Plasma filaments are longer and firing at a higher rate. There is an almost continuous effect in the air. »

What is the next step ?

“We are in the process of improving our laser guidance. There is also work on the positioning of lightning in clouds. Currently, we can predict with an accuracy of one kilometer where the lightning will be. We would like it to be more precise. »

A new outdoor test will be done within a year, if the funding is there.

Another point to improve: Mr. Houard’s technology only works with “positive” lightning, which comes from positively charged clouds. “Most lightning strikes occur in negatively charged clouds,” he says.

Research on laser guidance of lightning has been around since the 1970s. “But it’s only been 25 years since we’ve had lasers powerful enough to consider it,” says Houard.