Pentagon-funded team developing high-powered laser to trigger lightning and rain

Researchers are working to develop a technique to trigger rain or lightning with high-energy laser beams.

Stimulating static-charged particles in clouds with the right kind of laser could summon rain or lightning, scientists believe, but lasers cannot reliably be fired great enough distances for this to be practical.

A team of scientists from the University of Central Florida and the University of Arizona think that lasers could be fired at greater distances if a secondary beam is used as an energy reservoir to prevent the breakdown of the high-intensity primary beam.

They recently published a report, "Externally refueled optical filaments," on their project in Nature Photonics.

Although lasers can travel great distances, they tend to collapse inward on themselves when a beam becomes too intense.

European researchers produced artificial ice clouds last year using high-power, ultrashort laser pulses focusing on cirrus clouds in the upper troposphere, where weather occurs.

But lightning strikes have not thus far been triggered by lasers because high-intensity beams are dispersed as plasma when electrons in the air’s oxygen and nitrogen are excited by the beams.

"What would be nice is to have a sneaky way which allows us to produce an arbitrary long 'filament extension cable,'” said Matthew Mills, a graduate student in the Center for Research and Education in Optics and Lasers.

He said that wrapping a large, low-intensity beam around the stronger beam like a doughnut could provide this arbitrary extension.

Mills and another graduate student, Ali Miri, have been able to extend the pulse from 10 inches to about 7 feet, and they’re working to extend their laser pulses even further.

"This work could ultimately lead to ultra-long optically induced filaments or plasma channels that are otherwise impossible to establish under normal conditions," said professor Demetrios Christodoulides, who is working with the students on the project.

In theory, he said, this principle could extend lasers for about 165 feet.

Development of this technology was supported by a $7.5 million grant from the Department of Defense.

The researchers say their technique could be used in long-distance sensors to divert lightning strikes away from buildings or in spectrometers that can identify chemical makeup.

Watch this video report posted online by GeoBeats News:

[Image: Lightning strike via Shutterstock]