Scientists begin to direct lightning with lasers – here’s how

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Lightning may look beautiful, but it kills thousands of people each year, does massive damage to buildings and infrastructure, and causes blackouts.

The only protection we have is lightning rods invented 300 years ago that only protect a small area.

The cost of damage to buildings by lightning strikes is difficult to estimate globally, but in the US in 2020 insurance company payments to cover repairs to homes and businesses were roughly US$2 billion (£1.6 billion). Insurance data from the UK shows that the costs of covering lightning strikes are rising.

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The problem is only likely to get worse, as the climate crisis has led to an increase in wildfires worldwide that have fueled lightning strikes. A 2014 study suggested that for every degree (Celsius) of global warming, the number of strikes increased by 12%.

Lighting sticks have their uses, but scientists are looking for a better way to control where lightning strikes, and lasers may be the solution, according to a new study.

how did they do

This latest experiment was carried out near a telecommunications tower on mountain Säntis in Switzerland – about 100 times a year, although the tower itself is protected by a lightning rod – often struck by lightning.

The results of the study found that lightning flowed in an almost straight line near the laser pulses, but the lightning pulses were more randomly distributed when the laser was turned off.

While this study is not the first attempt at guiding lightning paths, it is the first to show that this can be done. The scientists attributed this to the high-power laser they used and the high altitude. At higher altitudes the air is less dense. This makes it easier for the current to pass, meaning that future experiments at sea level will require a more powerful laser.

<sınıf aralığı=At the summit of Säntis (2500m), the laser was focused on a 124m-high transmitter tower equipped with a conventional lightning rod. Martin Stollberg/© TRUMPF” data-src=”https://s.yimg.com/ny/api/res/1.2/k19pRsmO8RE7Zq5QEmdeaw–/YXBwaWQ9aGlnaGxhbmRlcjt3PTk2MDtoPTY0MA–/https://media.zenfs.com/en_/thec516475759cc156b/https://media.zenfs.com/en_/thec564564f7media.zenfs564b075576564f
At the summit of Säntis (2500m), the laser was focused on a 124m-high transmitter tower equipped with a conventional lightning rod. Martin Stollberg/© TRUMPF

To understand how scientists use light to change the path of electricity, you need to understand what lightning actually is: the flow of charged particles from one location to another. Particles in clouds are mostly electrically neutral when they form, but they generate both positive and negative charges. The cloud wants to be neutral by exchanging charge with the ground.

The type of lighting most people are familiar with is jagged bright flashes of light between the ground and clouds, but there are other types. Lightning can travel between clouds. It can also move from the clouds upwards into the atmosphere. This can even produce strings of red air glows where the thinner atmosphere warms. This heat energy is then released as light.

As the charge in the cloud builds up, it reaches incredibly high voltages (roughly equivalent to 8 million car batteries connected together), which creates a path in the air. The electrical current required to separate air components is usually around 300 million volts per square metre.

The thrust of this enormous voltage in electrically charged (ionized) air allows the charge to flow down the cloud and discharge onto the ground or nearby buildings. This current flow will follow the most electrically conductive path.

For this reason, lightning rods are sometimes used to protect buildings from lightning. Metal is more conductive than air, so if you place a large rod in the ground, lightning will have an easier path than through air. It can only protect a small area though.

Many researchers think that some lightning storms may be caused by cosmic rays (high-energy particles from outside the solar system). These particles pass through the atmosphere and interact with the air to create an ionized path along their direction of motion. That’s a split theory that researchers have as to whether it affects the total number of lightning strikes around the world.

The scientists used a powerful laser to try and create ionizing pathways, similar to the cosmic ray theory. Sending fast (1,000 times per second) energetic pulses with a laser heats and ionizes the air, making it conductive for a short time. The lightning strike will have less resistance along this path and will be more prone to flow that way.

If this technology is perfected, it could one day help protect infrastructure such as airports and nuclear power plants. It can even be used in a more advanced form to protect homes using lasers from a safe distance. However, it’s unlikely to launch near you anytime soon, if for no other reason than power costs.

This article has been republished under a Creative Commons license from The Conversation. Read the original article.

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Ian Whittaker does not work for, consults, owns shares, or receives funding from any company or organization that might benefit from this article, and has not disclosed any relevant affiliations beyond his academic appointments.

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