RESEARCHES OF WHISTLERS
Abstract
A station for analysis of relations between lightning discharges and whistlers was operated near Uppsala. After preliminary tests in 1956-57 a definite program was realized during the thunderstorm season of 1958. It was found that whistlers occur in groups - whistler situations with periods often of 1/2-2 1/2 hours, exceptionally of 5-6 hours. Whistlers sometimes occurred in great numbers for shorter periods of time between total cessations. These extended over hours, days and even weeks. Whistler situations on days with thunderstorms were located by a CRO direction finder. It was found that while a thunderstorm in one direction produced whistlers, a simultaneous thunderstorm in another direction at about the same distance sometimes did not. Variations in the same thunderstorm of the electric field force from atmospherics related or not to whistlers resulted in that atmospherics with the highest field force were always followed by whistlers. This was explained partially by facilitated propagation for wavepackets in the low-frequency band around 5 kc and partially by high initial energy in the discharges causing whistlers. A comparison in the same thunderstorm of waveforms from atmospherics not producing whistlers showed typically irregular variational forms and one single discharge in the lightning path. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1959
- Accession Number
- AD0267353
Entities
People
- Harald Norinder
Organizations
- Uppsala University