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How Laser Beams Can Trigger and Control Lightning Bolts

By Wesley Fenlon

Imagine a laser lightning rod that could safely divert dangerous strikes or strategically direct a powerful current of electricity.

Science asks heavy questions. Is there life on other planets? How old is the universe? How can we make the ability to harness lightning even cooler? That last one has been definitively answered by a team of researchers at ENSTA-ParisTech's Applied Optics laboratory, who managed to divert an arc of lightning using a powerful laser beam. Controlling lightning with laser beams? A futuristic version of Frankenstein's Lab is just around the corner.

New Scientist breaks down how lasers can control--and even trigger--a bolt of lightning:

Lasers were developed that could generate terawatts (trillions of watts) of power for femtoseconds (millionths of billionths of a second). These created pulses so intense that they ripped electrons from air molecules, forming channels of ionised air along the beam path. These paths focused the laser light in high intensity zones called filaments, which kept the air ionised long after the laser passed through, but failed to trigger or direct lightning.

Photo Credit: Flickr User Zokuga via Creative Commons.

The scientists from ParisTech tested out their five terawatt laser almost exactly four years ago in 2008 but weren't actually able to summon forth heavenly wrath and guide it along the path of the laser. A few more years of work brought that goal to fruition in a lab environment. The team set up a high voltage generator to simulate lightning and were able to guide the current from its natural path to the closer of two electrodes. The laser-guided discharge is straight as an arrow.

In that test, the more remote electrode was only 2.5 meters away. Another test proved the ability to guide an electric discharge at a distance of 50 meters. Combined, the success of the two tests bodes well for a laser lightning rod that could safely divert dangerous strikes or strategically direct a powerful current of electricity. The key result of the latter experiment is being able to control lightning without the laser making contact with an electrode.

If we can do that, we can theoretically do the same thing by firing a laser into a thunderhead. Distance will remain a hurdle, since the laser will be hundreds of meters, if not further, away from the source of lightning. But the scientists don't seem too ruffled: their recent research paper concludes with a reminder that "ionization induced by filamentation has been measured recently up to 1 km distance from the laser."