August 25, 2009

Scientist get image of huge lightning jet

U.S. scientists say they've captured a one-second image and the electrical fingerprint of a gigantic lightning jet that flowed 40 miles upward from a storm.

While not occurring every time a thunderstorm develops, the rarely seen, highly charged meteorological events can flash up to the lower levels of space, or the ionosphere, Duke University scientists said. They are substantially larger than their downward striking cousins.

Despite poor viewing conditions as a result of a full moon and a hazy atmosphere, we were able to clearly capture the gigantic jet, said study leader Steven Cummer, an electrical and computer engineer at Duke University in North Carolina.

Images of gigantic jets have only been recorded on five occasions since 2001. The Duke University team caught a one-second view and magnetic field measurements that are now giving scientists a much clearer understanding of these rare events.

This confirmation of visible electric discharges extending from the top of a storm to the edge of the ionosphere provides an important new window on processes in Earth's global electrical circuit, said Brad Smull of the National Science Foundation, which funded the research.

The research that also included Jingbo Li, Feng Han, Gaopeng Lu, Nicolas Jaugey, Walter Lyons and Thomas Nelson appears in the online edition of the journal Nature Geoscience.