Scientists developing laser that could control the weather

Ever since suffering through Mother Nature's first drought, humans have wanted to control the weather.

It might soon be possible, if researchers at the University of Arizona and University of Central Florida's College of Optics & Photonics are successful in developing a high-energy laser that could, in theory, induce rain or lightning when pointed at clouds.

According to a report published in the journal
Nature Photonics, the beam would be able to activate static electricity in the clouds, creating storms on demand.The trick is to create the right kind of laser.
"When a laser beam becomes intense enough, it behaves differently than usual — it collapses inward on itself,” Matthew Mills, a graduate student at the Center for Research and Education in Optics and Lasers, told UCF Today. “The collapse becomes so intense that electrons in the air’s oxygen and nitrogen are ripped off creating plasma — basically a soup of electrons.”

More from their report:

    At that point, the plasma immediately tries to spread the beam back out, causing a struggle between the spreading and collapsing of an ultra-short laser pulse. This struggle is called filamentation, and creates a filament or “light string” that only propagates for a while until the properties of air make the beam disperse.

The researchers are working on what they call a "filament extension cable" to withstand the collapse.

"If you wrap a large, low-intensity, doughnut-like ‘dress’ beam around the filament and slowly move it inward, you can provide this arbitrary extension,” Mills said. “Since we have control over the length of a filament with our method, one could seed the conditions needed for a rainstorm from afar. Ultimately, you could artificially control the rain and lightning over a large expanse.”

Other less controversial uses include long-distance sensors or guiding microwave signals along long plasma channels that would be impossible otherwise, UCF professor Demetrios Christodoulides told CBS News.

While it might sound like a pipe dream, the federal government is interested in the idea. The development of the cloud-laser technology is being backed by a $7.5 million grant from the U.S. Department of Defense.