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Subionospheric VLF signatures of nighttime D region perturbations in the vicinity of lightning discharges

Journal Article · · Journal of Geophysical Research; (United States)
; ;  [1];  [2]
  1. Stanford Univ., CA (United States)
  2. State Univ. of New York, Albany (United States)

A 12-hour sequence of perturbations of subionospheric VLF signals observed in association with lightning provided preliminary evidence that the ionospheric regions perturbed in these events may be confined to within {approximately} 150 km of the lightning discharges, and that intracloud flashes as well as cloud-to-ground lightning may be important in producing the perturbations. High-resolution analysis of event signatures indicated the presence of two different classes of events. For one set of events, observed during the most active central 6 hours of the observations period, a {approximately} 0.6-s delay between the causative lightning and VLF event onset and a {approximately} 1-s onset duration was observed, consistent with previously suggested models of the gyroresonant whistler-paritcle interaction that leads to particle precipitation and perturbation of the Earth-ionosphere waveguide. However, another set of events, observed during the first 2 hours of the observation period, exhibited a very different temporal signature, characterized by a much smaller ({lt}50 ms) delay and sometimes also very short (< 50 ms) rise times. Such events are possibly related to previously reported cases of similarly early/fast events and may involve a more direct coupling between the lightning discharge and the lower ionosphere.

OSTI ID:
5963244
Journal Information:
Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 93:A10; ISSN JGREA; ISSN 0148-0227
Country of Publication:
United States
Language:
English