The Source Regions of Whistlers. Issue 7 (4th July 2019)

• Record Type: Journal Article
• Authors: Koronczay, Dávid; Lichtenberger, János; Clilverd, Mark A.; Rodger, Craig J.; Lotz, Stefan I.; Sannikov, Dmitry V.; Cherneva, Nina V.; Raita, Tero; Darrouzet, Fabien; Ranvier, Sylvain; Moore, Robert C.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 7(2019)
• Page Start: 5082
• Page End: 5096
• Publication Date: 2019-07-04
• Subjects: VLF -- whistlers -- lightning -- ducted -- sferics; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA026559
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: We present a new method for identifying the source regions of lightning‐generated whistlers observed at a fixed location. In addition to the spatial distribution of causative lightning discharges, we calculate the ratio of lightning discharges transmitted into ground detectable whistlers as a function of location. Our method relies on the time of the whistlers and the time and source location of spherics from a global lightning database. We apply this method to whistlers recorded at 15 ground‐based stations in the Automatic Whistler Detector and Analyzer Network operating between 2007 and 2018 and to located lightning strokes from the World Wide Lightning Location Network database. We present the obtained maps of causative lightning and transmission rates. Our results show that the source region of whistlers corresponding to each ground station is around the magnetic conjugate point of the respective station. The size of the source region is typically less than 2, 000 km in radius with a small fraction of sources extending to up to 3, 500 km. The transmission ratio is maximal at the conjugate point and decreases with increasing distance from it. This conforms to the theory that whistlers detected on the ground propagated in a ducted mode through the plasmasphere, and thus, the lightning strokes of their causative spherics must cluster around the footprint of the ducts in the other hemisphere. Our method applied resolves the whistler excitation region mystery that resulted from correlation‐based analysis methods, concerning the source region of whistlers detected in Dunedin, New Zealand. Key Points: We present a method for identifying the geographical source regions of lightning‐generated whistlers Whistler source regions corresponding to 15 fixed whistler detector ground stations are determined Whistler transmission rates as a function of location are also determined