An experimental evidence of non-ducted propagation during daytime from theESD whistler observations at low latitude ground station Jammu

Citation
Mk. Lalmani,"babu et al., An experimental evidence of non-ducted propagation during daytime from theESD whistler observations at low latitude ground station Jammu, EARTH MOON, 84(3), 1999, pp. 151-162
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
EARTH MOON AND PLANETS
ISSN journal
0167-9295 → ACNP
Volume
84
Issue
3
Year of publication
1999
Pages
151 - 162
Database
ISI
SICI code
0167-9295(1999)84:3<151:AEEONP>2.0.ZU;2-X
Abstract
The propagation mechanism of low latitude daytime whistlers is investigated on the basis of ground measurements made continuously during daytime in No rth India at Jammu (geomag. lat. 22 degrees 26 degreesN; L = 1.17). On Febr uary 14, 1998 extremely small dispersion (ESD) whistlers with dispersion va rying from 5-10 sec(1/2) in surprisingly large numbers were recorded at Jam mu during daytime in the late afternoon. The results of a study of the char acteristics of ESD whistlers are presented and the discussion indicates tha t ESD whistlers recorded are the VLF waves radiated from the return stroke of the lightning discharge launched at the ionosphere with different initia l wave normal angles, propagated upwards under either quasi-longitudinal co nditions or pro-longitudinal whistler mode, turned around at different heig hts due to quasi-transverse propagation and received at Jammu with the disp ersion of the order of 5-10 sec(1)/2. The validity of this suggestion has b een tested by performing actual ray-tracing computations in the presence of equatorial anomaly model.