The adage \u201cEveryone complains about the weather but nobody does anything about it,\u201d may one day be obsolete if researchers at the University of Central Florida\u2019s College of Optics & Photonics and the University of Arizona further develop a new technique to aim a high-energy laser beam into clouds to make it rain or trigger lightning.<\/p>\n
The solution? Surround the beam with a second beam to act as an energy reservoir, sustaining the central beam to greater distances than previously possible. The secondary \u201cdress\u201d beam refuels and helps prevent the dissipation of the high-intensity primary beam, which on its own would break down quickly. A report on the project, \u201cExternally refueled optical filaments,\u201d was recently published in Nature Photonics.<\/p>\n
Water condensation and lightning activity in clouds are linked to large amounts of static charged particles. Stimulating those particles with the right kind of laser holds the key to possibly one day summoning a shower when and where it is needed.<\/p>\n
Lasers can already travel great distances but \u201cwhen a laser beam becomes intense enough, it behaves differently than usual \u2013 it collapses inward on itself,\u201d said Matthew Mills, a graduate student in the Center for Research and Education in Optics and Lasers (CREOL). \u201cThe collapse becomes so intense that electrons in the air\u2019s oxygen and nitrogen are ripped off creating plasma \u2013 basically a soup of electrons.\u201d<\/p>\n
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 \u201clight string\u201d that only propagates for a while until the properties of air make the beam disperse.<\/p>\n
\u201cBecause a filament creates excited electrons in its wake as it moves, it artificially\u00a0seeds\u00a0the conditions necessary for rain\u00a0and lightning to occur,\u201d Mills said. Other researchers have caused \u201celectrical events\u201d in clouds, but not lightning strikes.<\/p>\n
But how do you get close enough to direct the beam into the cloud without being blasted to smithereens by lightning?<\/p>\n
\u201cWhat would be nice is to have a sneaky way which allows us to produce an arbitrary long \u2018filament extension cable.\u2019 It turns out that if you wrap a large, low intensity, doughnut-like \u2018dress\u2019 beam around the filament and slowly move it inward, you can provide this arbitrary extension,\u201d Mills said. \u201cSince we have control over the length of a filament with our method, one could\u00a0seed the conditions needed for a rainstorm from afar. Ultimately, you could artificially\u00a0control the rain and lightning over a large expanse with such ideas.\u201d<\/p>\n
So far, Mills and fellow graduate student Ali Miri have been able to extend the pulse from 10 inches to about 7 feet. And they\u2019re working to extend the filament even farther.<\/p>\n
\u201cThis work could ultimately lead to ultra-long optically induced filaments or plasma channels that are otherwise impossible to establish under normal conditions,\u201d said professor Demetrios Christodoulides, who is working with the graduate students on the project.<\/p>\n
\u201cIn 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.\u201d<\/p>\n
Other possible uses of this technique could be used in long-distance sensors and spectrometers to identify chemical makeup. Development of the technology was supported by a $7.5 million grant from the Department of Defense.<\/p>\n","protected":false},"excerpt":{"rendered":"The adage \u201cEveryone complains about the weather but nobody does anything about it,\u201d may one day be obsolete if researchers at the University of Central Florida\u2019s College of Optics & Photonics and the University of Arizona further develop a new technique to aim a high-energy laser beam into clouds to make it rain or trigger lightning. The solution? Surround the…","protected":false},"author":11,"featured_media":58733,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"template-twocol.php","format":"standard","meta":{"_acf_changed":false,"lazy_load_responsive_images_disabled":false,"footnotes":"","_links_to":"","_links_to_target":"","_wp_rev_ctl_limit":""},"categories":[23,24],"tags":[7080,981,1112,1268],"tu_author":[],"class_list":["post-58732","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","category-science-technology","tag-center-for-research-and-education-in-optics-and-lasers","tag-college-of-optics-and-photonics","tag-creol","tag-demetrios-christodoulides"],"yoast_head":"\n