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From Lightning Rods to Laser Beams: The Evolution of Lightning Protection

Lightning strikes are electrical discharges that occur within thunderstorms. Lightning is created when there is a build-up of electrical charges within a storm cloud, and the charges are released in a sudden burst of energy. The discharge can occur within the cloud, between clouds, or between the cloud and the ground.

When lightning strikes the ground, it can cause a number of different effects, including fires, damage to buildings, and injury or death to people and animals.

Lightning strikes can cause a wide range of damage, depending on the intensity and location of the strike. One of the most common forms of damage is fire. When lightning strikes a flammable object such as a tree or building, it can ignite the object and quickly spread, causing significant damage.

Electrical damage is another common effect of lightning strikes. The electrical surge from a strike can damage appliances, electronics, and other electrical equipment, often requiring costly repairs or replacements.

Lightning strikes can also cause structural damage to buildings, bridges, and other structures. The force of the strike can create explosions, shatter concrete, or crack foundations, which can be dangerous and costly to repair.

Lightning strikes can also cause injury or death to humans and animals, and can result in power outages by damaging electrical infrastructure such as transformers, power lines, and substations.

Finally, ground damage is also a possibility, as a strike can create deep craters or fracture rocks. Given the potential for significant damage caused by lightning strikes, it is important to take precautions during thunderstorms to avoid being struck.

Lightning is a frequent occurrence worldwide with an estimated 50 occurrences per second and 20% of those resulting in ground strikes.  It is impossible to know exactly, but it is estimated that worldwide there are approximately 24,000 fatalities with ten times as many injuries annually due to lighting.  Most of these incidents are avoidable.

 

Protection from lightening strikes

It is important to take precautions during thunderstorms to avoid being struck by lightning, such as seeking shelter in a sturdy building or a hard-topped metal vehicle, and avoiding open areas, tall objects, and bodies of water.

Lightning rod

A lightning rod is a device designed to protect buildings and other structures from the damaging effects of lightning strikes. Also known as a lightning conductor or air terminal, a lightning rod works by providing a path of least resistance for lightning to follow, which directs the electrical current safely to the ground, rather than allowing it to travel through the building and cause damage.

The lightning rod typically consists of a metal rod or conductor that is attached to the highest point of the building, such as the roof or chimney. The rod is connected to a network of conductive wires that are buried in the ground, forming a conductive path from the top of the building to the earth.

When lightning strikes the building, the electrical current is attracted to the lightning rod, which provides a direct path for the current to flow through the conductive wires and into the ground. This protects the building and its occupants by preventing the current from flowing through the structure and causing damage or injury.

Lightning rods have been used for centuries and are a highly effective means of protecting buildings from lightning strikes. However, it’s important to note that they do not prevent lightning from striking a building altogether. Rather, they redirect the electrical current away from the structure and into the ground, minimizing the potential for damage.

 

Rocket-and-wire technique

The rocket-and-wire technique is a method of artificially triggering lightning. The basic principle behind this technique is to create a path of ionized air between a storm cloud and the ground, which would attract a lightning strike and direct it away from vulnerable areas.

The process typically involves launching a small rocket attached to a thin wire into a storm cloud. As the rocket ascends, it releases a stream of conductive material, such as potassium or sodium, which creates a conductive path through the air. Once the rocket reaches a certain altitude, it is designed to trigger a lightning strike by creating a channel of ionized air that extends from the cloud down to the ground, along the length of the wire.

The rocket-and-wire technique has been used in research to study the physics of lightning and to test lightning protection systems. However, it has not been widely adopted as a method of lightning protection, as it is expensive, requires specialized equipment and expertise, and can be dangerous if not properly executed.

Additionally, there are concerns about the potential unintended consequences of artificially triggering lightning. For example, if the rocket-and-wire technique is used in an area with flammable materials, such as a forest or oil refinery, it could start a wildfire or cause an explosion.

Overall, the rocket-and-wire technique remains an experimental method of artificially triggering lightning, and its use for lightning protection is limited. The most effective way to protect against lightning strikes is still through the use of traditional lightning protection systems, such as lightning rods and surge protectors.

 

Laser lightning protection

Laser technology has been proposed as a potential alternative to traditional lightning rods for protecting buildings and other structures from lightning strikes. The idea is based on the fact that lasers can create an ionized channel in the air, which could provide a path of least resistance for lightning to follow, similar to a lightning rod.

The basic principle behind laser lightning protection is to fire a high-powered laser beam into the sky, creating a narrow ionized channel that extends from the ground up into the atmosphere. This channel is designed to be more conductive than the surrounding air, providing a path of least resistance for the lightning to follow.

When lightning strikes, the electrical current would be directed along the ionized channel and into the ground, much like the way a lightning rod works. Because the ionized channel is created only when needed, rather than being a permanent fixture on the building, it may be a more aesthetically pleasing option for some building owners.

While the concept of laser lightning protection is still in the experimental stages, early results have been promising. Researchers have successfully created ionized channels using lasers and demonstrated that they can guide electrical currents in the laboratory. However, it is still unclear whether this technology can be scaled up to protect larger structures, or whether it will be cost-effective compared to traditional lightning rods.

Recent Demonstration

A group of scientists recently set up a laser array near a 124m telecom tower atop Switzerland’s Säntis mountain. The structure is the recipient of over a hundred lightning strikes annually, making it a prime attractor for the experiment. Between July and September of last year, the lasers fired into a number of stormfronts over a total of six hours. According to researchers’ measurements, the laser pulses influenced the course of four upward discharges, although only one took place in clear enough conditions to photograph using high-speed cameras. Still, the lightning’s path in that instance appears to have been diverted around 50m towards the laser beam.

The system works thanks to the lasers’ ability to forge a more convenient path for lighting to travel towards the Earth. The surrounding air’s refractive index changes as the pulses fire at over 1,000 times per second into the storm clouds, making them contract and intensify so much that they ionize surrounding air molecules. A channel of ionized, low density air is then created from the air molecules quickly heating and spreading at supersonic speeds. Although these “filaments” as researchers describe them only last mere milliseconds, their conductivity compared to surrounding air make a much easier path for lightning arcs. Early indications also point to the laser lightning rods’ diversion range being much wider than traditional metal rods, which ostensibly cover an area about twice as wide as the rod is tall.

There are some immediate drawbacks to this new system, however. For one, the laser pulses are (perhaps unsurprisingly) extremely bright, and could easily pose issues for any potential nearby pilots—hence closing the airspace around the experiment during its runtime. Then there’s the system’s roughly $2 million price tag during the experiment’s five year development that eventually saw the enlisting of Switzerland’s largest helicopter to help build the laser system’s home atop Säntis. All of that makes it very unlikely to see laser lightning rods atop suburban homes thanks to the comparatively very cheap land-based rod.

That said, such a system could be more cost-effective for places like military bases, extremely tall structures, and spaceports with generally far more expensive repair costs than the average home following lightning strikes.

The article highlights the damage that lightning strikes can cause to critical infrastructure, such as power grids, transportation systems, and communication networks. It also outlines the risks posed by lightning strikes to the environment, including the potential for wildfires and damage to ecosystems.

The authors argue that as climate change increases the frequency and intensity of lightning strikes, infrastructure must be resilient enough to withstand these natural disasters.

The authors propose a multi-faceted approach to lightning protection, which includes the development of new materials and technologies, improved lightning detection and monitoring systems, and better coordination among different sectors of infrastructure management. They also emphasize the importance of public education and awareness campaigns to encourage responsible behavior during thunderstorms.

Overall, the article emphasizes the need for infrastructure planners and policymakers to take lightning protection seriously as a critical component of resilience in the face of natural disasters. It calls for a collaborative effort among researchers, industry leaders, and government officials to develop and implement effective lightning protection strategies.

 

Overall, laser lightning protection is an exciting area of research that could have the potential to revolutionize the way we protect buildings and other structures from lightning strikes in the future.

 

References and Resources also include:

https://www.popsci.com/technology/laser-beam-lightning-rod/

https://www.nature.com/articles/s41566-022-01139-z?utm_medium=affiliate&utm_source=commission_junction&utm_campaign=CONR_PF018_ECOM_GL_PHSS_ALWYS_DEEPLINK&utm_content=textlink&utm_term=PID100060515&CJEVENT=a84053fcc17411ed83f1eeb80a18b8f8

About Rajesh Uppal

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