Researchers Develop Laser That Could Influence Weather

Researchers like Matthew Mills, a graduate student at the University of Central Florida’s College of Optics and Photonics, in collaboration with the University of Arizona and other schools nationwide are working on advances in laser technology that could make it rain. Literally. This network of researchers is developing a new technique that could aim a high-energy laser beam into the clouds to trigger rain and lightning.

The project utilizes a process called filamentation, which occurs when a laser beam becomes so intense that it collapses inward on itself, creating plasma as electrons shoot off from the oxygen and nitrogen in the air. The plasma then tries to spread the beam back out only to collapse once again. This spreading and collapsing creates a filament or string of light that dissipates over distance.

Condensation and lightning activity are linked to large amounts of static charged particles in the clouds. Because a filament creates excited electrons, it can mimic the conditions necessary for thunderstorms to occur. The idea of shooting a high-energy laser beam into the clouds to stimulate a rainstorm is a decade old.  However, prior to innovations by students like Mills, the project was limited by the distance a beam could travel. The solution came in an epiphany after some trial and error: surround the beam with a second beam, a “dress” beam, to reinforce the initial beam before it dissipates by refueling as it lengthens. The dress beam extends the distance to which a laser beam can travel, creating the potential for a number of applications. So far, researchers on the project have extended the filament from ten inches to about 7 feet, and with this success, are able to obtain the resources to extend the beam as far as they want.

The ability to stimulate rain and lightning could allow humans to trigger a storm early to prevent major storm damage to populated areas or help out a farmer whose crops are dying of thirst. However, the conditions for rain and lightning must already be present. The laser does not create thunderstorms, but does allow for some control over when they occur.

The extended distance of filaments contributes to safer practices in “remote detection spectroscopy,” a process which can be used to determine the configuration of chemicals and potentially poisonous gases in an area. Mills explains that the scattering from filaments carry information to researchers in a fingerprint of sorts, allowing scientists to read the composition of elements in an area from a safe distance.

The work of Mills and other researchers on the project has attracted national and international attention in both academic and popular press. The United States Air Force supported the general development of the filamentation with a five million dollar grant.