It's not quite Zeus, but at least it's not entirely a myth as lasers have been used for the first time to trigger and divert lightning bolts, the New Scientist reports.
In the 1990s, the idea of using a powerful laser to create a low-resistance path through the atmosphere gained momentum, Jeff Hecht writes. The "virtual lightning rod", or the lasers that were developed could create terawatts (trillions of watts) of power for femtoseconds (millionths of billionths of a second.) These lasers created pulses so intense they ripped electrons from air molecules, forming channels of ionized air along the beam path. These paths, called filaments, kept the air ionized long after the laser passed through, although they failed to trigger direct lightning.
In 2008, a group led by Andre Mysyrowicz, with applied optics laboratory at ENSTA Paris Tech in France, took a laser the size of a trailer to New Mexico to do field experiments with clouds. They figured out that laser filaments increased electrical activity in storm clouds. But again, it did not trigger lightning.
Now, the same group have reached two milestones on the road to practical lightning protection with a more compact laser. They experimented in a military lab in Tolouse, France, and set up a high-voltage discharge with two possible targets about 2.5 meters away. When the laser was off, the artificial lighting always hit the closer target. When he laser was on it generated a pathway to the target was farther away, but the discharge only went where it was directed.
In their second experiment, they aimed the laser beam 50 meters across from the lab that passed 5 to 20 centimeters from an oppositely charged electrode. Usually, lightning jumps straight from electrode to electrode, but with the laser on, the discharge jumped to the path and followed it before jumping to the second electrode.
Controlling the lightning without making contact with the electrodes makes this more like a real-world situation, Jerome Kasparian, of the University of Geneva, Switzerland, told the New Scientist. "In the clouds, you don't really have an electrode you can touch," he said. "But in the real world the targets are far more distant."
Mysyrowiicz's group is planning more field experiments in the future and Kasparian think they need a more powerful laser for it to be successful.
[ Via the New Scientist]
Image: Picols Photo/Camilo Paredes/Getty and the Laboratorie d'optique appliqué