Lightning rods have been used to safely guide strikes into the ground since Benjamin Franklin’s day, but their short range (roughly the same radius as the height) and fixed-in-place design makes them ineffective for protecting large areas. The technology may finally be here to replace them in some situations. European researchers have successfully tested a system that uses terawatt-level laser pulses to steer lighting toward a 26-foot rod. It’s not limited by its physical height, and can cover much wider areas — in this case, 590 feet — while penetrating clouds and fog.
The design ionizes nitrogen and oxygen molecules, releasing electrons and creating a plasma that conducts electricity. As the laser fires at a very quick 1,000 pulses per second, it’s considerably more likely to intercept lightning as it forms. In the test, conducted between June and September 2021, lightning followed the beam for nearly 197 feet before hitting the rod.
Researchers have been exploring laser lightning guides for years. However, experiments have typically been limited to much shorter distances and relatively slow pulses that were more likely to miss lighting as it formed. Dr. Aurélien Houard, who helped lead the project, told the Wall Street Journal that this laser shot 100 times more pulses per second than in previous attempts.
It could be a long while before lasers are used beyond experiments. The University of Glasgow’s Matteo Clerici, who didn’t work on the project, noted to The Journal that the laser in the experiment costs about $2.17 billion dollars. The discoverers also plan to significantly extend the range, to the point where a 33-foot rod would have an effective coverage of 1,640 feet.
If the scientists succeed, the breakthrough could make lightning protection viable across large areas. This would be particularly useful for safeguarding rocket launchpads, where lightning strikes can force mission delays if they’re too close to the flight path. They could also be helpful for protecting airports, power plants, forests and other sprawling locations where a strike could prove catastrophic.