Research press release


Nature Photonics

Physics: Laser in the sky diverts lightning strikes

空に向けて照射した強力なレーザーが仮想的な避雷針を形成し、落雷経路をそらす可能性があることを実証した論文がNature Photonicsに掲載される。今回の知見は、発電所、空港、発射台などの重要インフラを保護するよりよい避雷方法への道を開く可能性がある。


Aurélien Houardたちは、2021年の夏、スイス北東部のゼンティス山で実験を行い、レーザーで雷を誘導できるかどうかを調べた。最高で1000パルス毎秒で発射する大型車サイズのレーザー装置が、1年に100回ほど落雷を受ける電波塔の近くに設置された。雷雨活動時6時間を超える実験で、著者たちは、レーザーが4回の上向き雷放電の経路を変えることを観測した。観測結果は、雷で発生した高周波電磁場を用いて雷撃の位置を決定することによって裏付けられた。雷撃時のX線バーストの検出の増加によっても誘雷の成功が確認された。雷撃事象の1つは、ハイスピードカメラによって直接記録され、50メートル以上レーザー経路に追従することが示された。


A powerful laser aimed at the sky can create a virtual lightning rod and divert the path of lightning strikes, a paper published in Nature Photonics demonstrates. The findings may pave the way for better lightning protection methods for critical infrastructure, such as power stations, airports and launchpads.

To date, the most common lightning protection device is the Franklin rod, an electrically conducting metal mast that intercepts lightning discharges and guides them safely to the ground. Acting as a virtual, movable rod, a laser beam directed at the sky could offer an alternative. The idea of using intense laser pulses to guide lightning strikes has been previously explored in laboratory conditions. However, no field result previously exists that experimentally demonstrates lightning guiding by lasers.

Aurélien Houard and colleagues conducted experiments during the summer of 2021 on the Säntis Mountain in northeastern Switzerland to explore whether a laser could guide a lightning strike. A laser the size of a large car, that fires up to a thousand pulses per second, was installed near a telecommunications tower, which is struck by lightning around 100 times a year. Over more than 6 hours of operation during thunderstorm activity, the authors observed that the laser diverted the course of 4 upward lightning discharges. Their observations were corroborated using high-frequency electromagnetic waves generated by the lightning to locate the strikes. Increased detection of X-ray bursts at the time of the strikes also confirmed successful guiding. One of the strikes was directly recorded by high-speed cameras and shown to follow the laser path for over 50 metres.

The authors conclude that their findings extend the current understanding of laser physics in the atmosphere and may aid in the development of novel lightning protection strategies.

doi: 10.1038/s41566-022-01139-z


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