Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80% of downloaded waveform data. About 22.9% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1-3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L≥4.
Bibliographical noteFunding Information:
The authors wish to acknowledge partial support for this research from CRDF grant RUG1-7084-PA-13, from NOAA grant NA10OAR4320148, and from NSF grant 1443011. The authors wish to thank the World Wide Lightning Location Network (http://wwlln.net), a collaboration among over 50 universities and institutions, for providing the lightning location data used in this paper. The authors wish to acknowledge the Space Sciences Laboratory at University of Berkeley and the University of Minnesota for providing EFW data (data link: http://www.space.umn.edu/ rbspefw-data/, PI: John Wygant) and the University of Iowa for providing the EMFISIS data (data link: http://emfisis.physics.uiowa.edu/ data/index, PI: Craig Kletzing), both of which are instruments on board the Van Allen Probes.
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- whistler wave