Scientists Can Now Reroute Lightning Strikes
What do an infrared laser, a telecom tower and a lightning rod have in common? Atop the Säntis mountain in Switzerland, scientists have installed an infrared laser next to a telecom tower, with a lighting rod in hopes of redirecting lightning. The idea is that a powerful enough laser could grab hold of a lightning bolt and reroute its path through the sky.
Lightning Protection Today
On January 16th, in Nature Photonics, scientists have reported that such a laser has in fact bent lightning towards the rod. Prior tests were conducted in a lab setting and were sucessfull in wrangling the electricity, however, this was a first demonstration of the technique during an actual storm. The sucess of the experiment shows great potential for developing a better lighting protection technology in the near future.
Today’s most common anti-lightning tech is the classic lightning rod, a few meters long metal pole rooted to the ground. The metal’s conductivity lures in lightning that might otherwise strike nearby buildings or people, feeding that electricity safely into the earth. But the area shielded by a lightning rod is limited by the rod’s height.
How Does it Work?
The project is the brainchild of Aurélien Houard, a physicist at Institut Polytechnique de Paris in Palaiseau. "If you want to protect some large infrastructure, like an airport or a launching pad for rockets or a wind farm, then you would need, for good protection, a lightning rod of kilometer size, or hundreds of meters. Such a tall metal pole would be impractical. But a laser could reach that far, intercepting distant lightning bolts and ushering them down to ground - based metal rods", said the scientist.
Houard and his colleagues tested this idea atop the Säntis mountain in northeastern Switzerland. They set up a high - power laser in the vicinity of a telecommunications tower tipped with a lightning rod that is struck by lightning around 100 times every year. The laser was zoomed in at the sky for about six hours total during thunderstorms from July to September 2021. The laser emited short, intense bursts of infrared light at the clouds at the rate of about 1,000 times per second.
This sequence of light pulses ripped electrons off air molecules and knocked some air molecules out of its way, carving out a channel of low-density, charged plasma. This combination of effects made it easier for electric current to flow, meaning that a path of least resistance was created for the lightning to follow. Houard’s team tuned their laser so that it formed an electrically conductive pathway just above the tip of the tower. This allowed the tower’s lightning rod to intercept a bolt snagged by the laser before it zipped all the way down to the laser equipment.