Lightning can be diverted to a lightning rod with a laser, thereby increasing its protection. A European research team has confirmed this with tests on the Swiss mountain Säntis and has now presented the work. With the new technology, facilities could be better protected in the future for which classic lightning conductors are not ideal because they cannot be extended indefinitely. The team refers, for example, to airports, wind turbines and nuclear power plants.
Virtually extend the lightning rod
Classic lightning rods have changed little since their invention by US founding father Benjamin Franklin in the mid-18th century. the University of Geneva now explains. A conductive metal mast protects an area whose radius roughly corresponds to its height. With the laser, channels of ionized air could now be created, which more or less conduct the lightning and thus virtually extend the mast upwards. During the test on the Säntis, this protective radius was increased from 120 to around 180 m. In the long run, the team wants to add the laser to a 10m high lightning rod to protect an area with a radius of 500m.
The technology was tested on the Säntis because it is one of the structures hit by the most lightning in Europe. On the mountain is a 124 m high Swisscom telecommunications tower, on which several instruments for analyzing lightning are already installed. Between June and September 2021, the new laser was then always activated when a storm was forecast. At the same time, the area had to be closed to air traffic. They wanted to determine whether it makes a difference when the laser is activated and when it is not. However, it took almost a year to evaluate the immense amounts of data. It was then shown that the laser also works in adverse weather.
Two deflected lightning bolts
Like the team in one Article in the journal Nature Photonics explained, this was not the first attempt to use lasers to redirect lightning. Unlike in the USA in 2004 and in Singapore in 2011, however, this has now been successful. The team attributes this to the significantly higher pulse rate of the laser used. It therefore came to a frequency of 1000 Hertz. The team also observed the flashes with special cameras at a distance of one and a half and five kilometers, but these only worked when the weather was good. Two images published in the article show lightning literally wrapping itself around the laser and then striking the lightning rod on the tower.
(mho)
