If you shoot a laser into a thunderstorm will the beam act as a lightning rod due to the ionization of the air by the laser beam?
Asked by: Jerry Thero
A research group in Japan is exploring this concept. I recall seeing a photo in Scientific
American of the arc from a large Tesla Coil being guided in a straight line by a laser
pulse. Contrary to what one might assume, their laser was IR, not UV. The extremely high
power IR pulse caused dust and aerosols in the air to explode into a 'dotted line' of
plasma, and the arc then followed this conductive line in the air. There was an article
in 1997 by P. Mortensen in the magazine Laser Focus World about their more recent
accomplishments. They have moved outdoors and are attempting to create 'plasma columns'
above a tower during a thunderstorm. Alumina powder is injected into the air, and the
focused laser pulse causes the powder to become a plasma. Here's an online version:
Another group is using a UV eximer laser to excite oxygen and create a pair of ionized
paths through the air which are then connected to a pulsed high voltage supply and used as
a sort of 'weapon.' http://www.hsvt.org/
I would imagine that the channels ionized by this UV laser could act as lightning rods
during a thunderstorm. However, if oxygen is absorbing the laser light, the range becomes
extremely limited. Perhaps too much power is required for an ultraviolet 'lightning rod'
laser, and that's why the Japanese group is using IR instead?
Answered by: William Beaty, B.S., Electrical Engineer, Seattle
'Our job in physics is to see things simply, to understand a great many complicated phenomena, in terms of a few simple principles.'