Acoustic wave maps give insight into physics of lightning
Univ. of Florida, Florida Institute of Technology, SRI
MONTREAL — For the first time, scientists have precisely captured a map of the boisterous bang radiating from a lightning strike. The work could reveal the energies involved in powering some of nature’s flashiest light shows.
As electric current rapidly flows from a negatively charged cloud to the ground below, the lightning rapidly heats and expands the surrounding air, generating sonic shock waves. While scientists have a basic understanding of thunder’s origins, they lack a detailed picture of the physics powering the crashes and rumbles.
Heliophysicist Maher Dayeh of the Southwest Research Institute in San Antonio and colleagues sparked their own lightning by firing a long, Kevlar-coated copper wire into an electrically charged cloud using a small rocket. The resulting lightning followed the conductive wire to the ground. Using 15 sensitive microphones laid out 95 meters from the strike