Astrophysicist strikes blow to lightning theory
Model suggests electric fields cannot grow large enough to generate bolts.
17 November 2003
BETSY MASON
The conventional view of how lightning is produced is wrong, according to a Florida-based physicist.
Electrical fields in the atmosphere simply cannot grow large enough to trigger lightning, calculates Joseph Dwyer of the Florida Institute of Technology in Melbourne1. "This means back to the drawing board," he says.
Dwyer mainly studies high-energy particles in space. But two years ago, after moving to central Florida, one of the most lightning-prone areas of the world, he became intrigued by reports of huge gamma-ray and X-ray bursts associated with lightning. Such high-energy radiation tends to be seen only in outer space, as moving through Earth's atmosphere slows it down.
Most scientists believe lightning is generated when a giant electric field builds up in the atmosphere. Although no one has actually seen such a field, researchers assumed that this was simply because they hadn't looked hard enough.
When Dwyer factored the production of high-energy radiation into a model describing the build-up of electrical fields in thunderstorms, he got a shock. He found that the release of gamma-rays and X-rays diffuses the electric field, preventing it from becoming large enough to spark lightning.
http://www.nature.com/nsu/031110/031110-19.html
