Infrasonic waves generated by supersonic auroral arcs
Article first published online: 9 OCT 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 19, 16 October 2012
How to Cite
2012), Infrasonic waves generated by supersonic auroral arcs, Geophys. Res. Lett., 39, L19105, doi:10.1029/2012GL053587.(
- Issue published online: 9 OCT 2012
- Article first published online: 9 OCT 2012
- Manuscript Accepted: 10 SEP 2012
- Manuscript Received: 16 AUG 2012
- infrasonic waves
 A finite-difference time-domain (FDTD) model of infrasound propagation in a realistic atmosphere is used to provide quantitative interpretation of infrasonic waves produced by auroral arcs moving with supersonic speed. The Lorentz force and Joule heating are discussed in the existing literature as primary sources producing infrasound waves in the frequency range 0.1–0.01 Hz associated with the auroral electrojet. The results are consistent with original ideas of Swift (1973) and demonstrate that the synchronization of the speed of auroral arc and phase speed of the acoustic wave in the electrojet volume is an important condition for generation of magnitudes and frequency contents of infrasonic waves observable on the ground. The reported modeling also allows accurate quantitative reproduction of previously observed complex infrasonic waveforms including direct shock and reflected shockwaves, which are refracted back to the earth by the thermosphere.