Laser beams can divert lightning strikes
A powerful laser aimed at the sky can create a virtual lightning conductor and divert the path of lightning strikes, as demonstrated by experiments conducted by researchers on a mountain in Switzerland. Their findings, which have now been published in the scientific journal Nature Photonics, may pave the way for better lightning protection methods for critical infrastructure, such as power stations and airports.
Currently, the most common lightning protection device is the Franklin rod, a metal mast that intercepts lightning discharges and guides them into the ground. The idea of using intense laser pulses instead of a traditional lightning conductor has been previously explored in laboratory conditions.
Vernon Cooray, Professor of Electricity at Uppsala University, is one of the researchers who have now tested whether this method works in real thunderstorms, outside the laboratory. The experiments to investigate whether a laser could guide a lightning strike took place on Mount Säntis in north-east Switzerland. A laser the size of a car that fires up to a thousand pulses per second was installed near a telecommunications tower that is struck by lightning around 100 times a year.
Filmed using high-speed cameras
Having tested the laser for a period of six hours during thunderstorm activity, the researchers concluded that the laser had diverted the course of four upward lightning discharges. Their observations were corroborated by high-frequency electromagnetic waves generated by the lightning, which showed where lightning had struck. Observed increases in X-ray bursts at the time of the strikes also confirmed the success of the lightning diversions. One of the strikes was recorded on film by high-speed cameras and can be seen following the laser path for over 50 metres.
The authors of the journal article conclude that their findings extend the current understanding of laser physics in the atmosphere and may aid in the development of novel lightning protection strategies.