An observational investigation of very low frequency radio emissions originating from meteors

Abstract

This study presents results from five months of meteor observations that included simultaneous and nearby very low frequency (VLF) wave detections. We explore the plausibility of VLF emissions from meteors resulting in the documented phenomena of simultaneous optical and audio signatures with meteor events. Most previous attempts to observe VLF emissions from meteors have been limited in duration and/or in area covered during observations. With the extended duration and an observational network of three cameras and two VLF receivers across Colorado, an exhaustive approach was taken to detect meteor VLF emissions. The $\sim$650 events collected were closely inspected for any signs of emissions, with an emphasis on brighter meteors and fireballs. The VLF data was filtered using interference mitigation techniques to eliminate spurious signals that could obscure the VLF signals of interest. By comparing the VLF spectral content at the time of meteors and during control times, we search for very small changes in the signal that would be statistically correlated with meteor observation times. Despite these efforts, no VLF emissions have been detected that cannot be attributed to other sources. Most commonly, lightning-generated sferics coincident with the time of meteor events lead to false attributions to meteors.