Southwest Research Institute (SwRI) researchers have imaged the first acoustic signature of thunder, visually capturing the sound waves created by artificially triggered lightning.
While the general mechanics of thunder generation are understood, it is not particularly clear which physical processes of the lightning discharge contribute to the thunder we hear.
By studying the acoustic power radiated from different portions of the lightning channel, researchers can learn more about the origins of thunder as well as the energetic processes associated with lightning.
Dr. Maher A. Dayeh, a research scientist in the SwRI Space Science and Engineering Division, designed a large, sophisticated array of microphones to study the acoustic signature of thunder. Fifteen microphones, spaced one meter apart, were lined up 95 meters away from the rocket launch pad where the triggered lightning would strike. To image the vertical profile of the bolt, Dayeh used post-signal processing techniques and directional amplification of the data signals captured by the microphone array.
The technique revealed a distinct signature of thunder generated by the lightning strike. Future experiments could allow scientists to study the probable acoustic signatures of current pulses, step leader branches, and discharge channel zigzags independently.
Learn about an Accelerometer Sensors Network for Acoustic Diagnostics (MASNAD).