A high-powered laser has for the first time made it possible to deflect lightning from a storm, an achievement that could be used to protect critical infrastructure such as airports, power plants or launch pads.
A powerful laser projected into the sky has been able to deflect lightning from a storm for the first time. “This is the first time that the effect of a laser on lightning has been observed. Nobody had used this technology to protect an infrastructure until now,” assures EL MUDNO Aurlien Houard, main author of this experiment carried out in Switzerland whose details are published this week in the magazine Nature Photonics.
According to the authors of the international consortium that signed this research, their results could be applied to protect critical and sensitive infrastructures to electrical storms, such as airports, power plants or launch pads for space missions. In fact, as Aurlien Houard, a researcher at the Ecole Polytechnique de Paris, explains, “Arianegroup, a company specializing in equipment for airports and rocket launch platforms, is already participating in the project”. Ariane is the company in charge of launching most of the European Space Agency (ESA) missions from the Kur Spaceport, in French Guiana.
However, the researcher believes that the development of the application for commercial use “could take between 10 and 15 years,” says the scientist.
Currently, the most widely used instrument to try to avoid the effects of lightning is still the lightning rod, which was invented by Benjamin Franklin in 1752. The first model developed was named the “Franklin lightning rod” in homage to the American politician, scientist and inventor who contributed so much to to the investigation of electricity. The lightning rod is designed to attract ionized lightning from the air to conduct the discharge towards the ground so that it does not cause damage to people or buildings.
The idea of using lasers for this purpose, however, had been raised years ago although its feasibility had not been demonstrated until now. “The idea was initially proposed in the 1970s., and over the last 50 years there have been numerous studies both in the laboratory and in the field to try to make it happen. But nobody was able to observe any effect of the laser on the beam,” says Houard.
Until the 2000s, there were no lasers capable of ionizing air, first on the scale required by a laboratory, and later, in specific facilities. The first experiment of these characteristics was carried out in Berlin in 2002 with a four meter lightning simulator. It was there that they realized that, by adjusting the parameters, they could guide the discharge between two electrodes along the path of a laser. Later, they did another study in New Mexico, but they could not guide the electrical discharge, because the laser they had was very intense.
“Six years ago, with Professor Jean-Pierre Wolf of the University of Geneva, we had the idea to use a new laser technology recently developed by the German company Trumpf Scientific Lasers to test a new laser beam experiment. This was the beginning of this project”, details Houard.
An eight meter laser
The Laser Lighting Rod (LLR) project required to develop a new laser which has taken them about three years. The instrument measures eight meters in length and 1.5 meters in width, and emits a thousand pulses per second.
The choice of the sky where they carried out the experiment was another key aspect. It is estimated that every second, 50 lightning strikes in different parts of the world, but the problem is that it is not possible to know when and where they will strike. The place chosen to install the laser was an area close to the Torre Sntis, a facility in northeastern Switzerland that is systematically struck by lightning; each year, to the point that more than a hundred episodes are recorded each year. To place the instrument here, it was necessary to devise how to protect the laser from the changes in temperature, humidity and dust of this environment.
Finally, the experiment was carried out during the summer of 2021. During more than six hours of operations during thunderstorms, the authors observed that the laser deflected the path of four beams, observations that were corroborated by using high-frequency electromagnetic waves to locate the beams. One of the impacts was recorded directly by high-speed cameras and was shown to follow the laser path for more than 50 meters.
After three months of the campaign, they have collected a large amount of data that they continue to analyze. The next step, according to Aurlien Houard, “will be to increase the length and conductivity of the guide plasma channel and obtain more statistics to accurately quantify the effect of the laser.”
This type of laser, like the one developed for the experiment, is used mostly for laboratory research, but it can also be used as a source to produce X-rays, electron or proton beams for imaging applications or medical treatments, according to Houard.
THE PROBABILITY OF DYING FROM A LIGHTNING STRIKE
Although the chance of being struck by lightning in a given year is one in 500,000, lightning is one of the leading weather-related causes of death. In Spain, it is estimated that every year between 10 and 15 people die from this cause.
There are particularly favorable areas for electrical storms to occur. For example, in the US, Florida is the state where the most accidents are caused by falls, with more than 2,000 injuries registered in the last 50 years, according to data from the Centers for Disease Control and Prevention in the US.
According to data from the Meteorological Service of the Institute for the Ocean and the Atmosphere (NOAA) of the USA, Between 2010 and 2022, 270 people died in the US from lightning strikes, but hundreds of citizens are injured every year, some with permanent neurological damage.
No place outside is safe during a thunderstorm, so the main recommendation is to seek shelter in a closed place, and stay there until at least half an hour after hearing the last thunder or seeing the last lightning. Avoid taking shelter under a tree.
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