Shulou(Shulou.com)11/24 Report--

Two hundred years later, someone finally invented a new type of lightning rod. Lightning can walk more than 50 meters with long feet.

(photo source: Flickr + homemade) Writing | A Xian

Revision | Ziv

Just after Rain Water's solar terms, it means that another year of thunderstorm season is coming.

Although people have been studying lightning protection for many years, it is like being locked up by a trisomy. The lightning rod invented by Benjamin Franklin is still the most commonly used means of lightning protection.

What is Daoyou doing here?? | the working principle of gifer lightning rod is actually very simple. When there is a charged cloud layer in thunderstorm weather, the lightning rod and the top of the tall building accumulate a large amount of electric charge, and the air between the lightning rod and the cloud layer can easily be broken through and become a conductor. The charged cloud layer forms a path with the lightning rod, and the lightning rod is grounded, so the lightning rod can transfer the charge on the cloud to the earth, ensuring the safety of high-rise buildings.

However, the lightning protection capacity is limited by the height of the rod, and the radius of the protection area is roughly equal to the height of the lightning rod. For example, a 20-meter-high lightning rod can protect the area with a maximum radius of 20 meters from lightning. If you want to protect some large infrastructure, such as airports, you may need a lightning rod of several kilometers or hundreds of meters, which is too difficult and impractical.

Lightning rods installed on small buildings are usually small. The uncertainty of lightning in Pixnio keeps people in a passive position all the time, but with the development of science, is there any technology that can draw down lightning and trigger lightning actively?

A recent study published in the international academic journal Nature Photonics provides a new idea for active lightning induction: in thunderstorm weather, lightning can follow laser-induced filaments (formed by short and strong laser pulses in the sky) to "walk" a long distance, breaking through the short-distance protection limitation of lightning rods, thus realizing active lightning induction.

The idea of laser lightning was first put forward by Ball in 1974. later, scientists also tried the experiment of lightning strike guided by strong laser pulse in the laboratory, but due to the limitation of science and technology, the experiment was not carried out successfully in the wild and natural thunderstorm weather.

True artificial lightning (really not recommended) | the principle of gifer laser lightning rod (filament lightning rod) is to use a laser to quickly emit strong and short laser pulses into the clouds, each pulse carrying about one terawatt (1 trillion watts) of instantaneous energy in one picosecond (1/1000000000000 seconds). In the process of laser propagation in the air, the laser will self-focus into a "laser filament". This process is actually the self-focusing effect of the beam, which means that when the intense laser beam passes through the nonlinear medium, it will automatically gather into thin lines with a diameter of several microns.

At the same time, strong laser pulses ionize air molecules and produce free electrons, which in turn counteract the self-focusing of the beam. The two processes of laser self-focusing and off-focusing will reach balance in a short time and form an air channel along the path of the pulse. In this laser-penetrated millisecond air channel, a strange combination of low-density air and high-density electrons forms a very attractive orbit for electrons.

124m high telecom tower | reference [1] Aurelien é lien Houard, a French physicist, and his colleagues conducted experiments in the Alps in northeastern Switzerland and installed a high-power Yb:YAG laser near the telecom tower. It was chosen here mainly because this "unlucky" tower is struck by lightning about 100 times a year.

The researchers observed that during the thunderstorm season from July to September in 2021, lasers were emitted in the sky for a total of six hours, changing the direction of lightning discharges four times. In an image recorded by a high-speed camera on July 24, it was clearly observed that the lightning reined in its "teeth and claws", clinging to the laser beam and moving about 50 meters from its original position. In the observation records of the other three laser turns on, through the radio frequency detector, it can also be seen that lightning follows the laser.

Lightning: submissive, dare not say a word. | reference [1] has advantages and disadvantages. The core problem of laser lightning rod is: expensive! The experimental project costs about 4 million euros (about 29.34 million yuan), half of which is spent on building laser systems.

A rocket with wire at the bottom was also tried a long time ago, which is often called rocket-wire lightning technology.

How many disposable rockets must be lifted off in a thunderstorm? | during thunderstorm weather, YouTube technology predicts in advance and selects a fixed location to launch a small rocket that drags metal wires to the thunderstorm cloud, so that the wire can contact the electric field in the thunderstorm cloud and transmit lightning to the ground fixed position through the wire. This technology originated in the United States, and China is the third country in the world to master the technology of artificial lightning.

However, there are still many urgent problems to be solved in this technology, such as rockets and wires are disposable consumables, and the debris dropped by the rocket after being struck by lightning is dangerous, so it is not suitable for widespread use at this stage.

(Tu Yuan gifer) there is a small question. Can the Rockets be replaced by Sky Monkeys? (bushi

Source of cover: Flickr + homemade

Reference:

[1] https://www.nature.com/articles/s41566-022-01139-z

[2] https://www.thepaper.cn/newsDetail_forward_21585804

[3] https://en.wikipedia.org/wiki/Lightning_rocket

This article is from the official Wechat account: bring Science Home (ID:steamforkids), author: everything.

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