Abstract
OBSERVATION OF PERIODIC VLF EMISSIONS AND WHISTLERTRIGGERED PERIODIC VLF EMISSIONS AT LOW LATITUDE GROUND STATION JAMMU (L=1.17) AND THEIR INTERPRETATIONS
Dr. Rajou Kumar Pandita*
ABSTRACT
New experimental data on periodic VLF emissions and whistler - triggered periodic VLF emissions during a quiet period at low latitude ground station Jammu (geomag. lat 22026/N; L=1.17) is presented in this paper. The present finding is believed to be first such events reported from any of the low latitude ground stations during quiet times. The whistlers recorded during quiet times are one-hop, or short type and the travel times of short whistlers at 4kHz are found to be in the range of 0.15-0.26 sec. corresponding to dispersion in the range of 10-17 sec½.The short whistlers were observed continuously for a long period during quiet days in the frequency range normally between 2-5 kHz and are found to be triggered by periodic VLF emissions. From the detailed spectrum analysis of the whistler-triggered periodic emissions observed at Jammu, it is found that the time intervals between the consecutive periodic emissions are almost same with the time delays between any of the two successive hops of multiflash whistlers. The interesting point is that the Time period between any of the periodic VLF emissions and one-hop whistler traces is almost half of the time delay of a one –hop whistler of dispersion 12s1/2 as explained in this paper.
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