Researchers could trigger rain or even lightning by beaming a laser into the clouds.
The beam is surrounded by a second beam that acts as an "energy reservoir," a University of Central Florida news release reported.
The reservoir allows the laser to reach a greater distance than before; the secondary "dress" beam helps prevent the high-intensity primary laser from dissipating
Both water condensation and lightning are linked to static charged particles; these particles are activated using a laser.
"When a laser beam becomes intense enough, it behaves differently than usual - it collapses inward on itself," Matthew Mills, a graduate student in the Center for Research and Education in Optics and Lasers (CREOL), said in the news release. "The collapse becomes so intense that electrons in the air's oxygen and nitrogen are ripped off creating plasma - basically a soup of electrons."
The plasma then attempts to spread the laser back out, leading to a struggle between the "spreading and collapsing" of a laser pulse; this struggle is known as "filamentation."
"Because a filament creates excited electrons in its wake as it moves, it artificially seeds the conditions necessary for rain and lightning to occur," Mills said.
"What would be nice is to have a sneaky way which allows us to produce an arbitrary long 'filament extension cable.' It turns out that 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," he 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 with such ideas."
The researchers have successfully extended the pulse from 10 inches to seven feet in the study that could one day lead to ultra-long optically induced filaments and plasma channels that would never be possible under normal conditions.
"In principle such dressed filaments could propagate for more than 50 meters or so, thus enabling a number of applications. This family of optical filaments may one day be used to selectively guide microwave signals along very long plasma channels, perhaps for hundreds of meters," professor Demetrios Christodoulides said in the news release.
