Propagation of Whistlers to Polar Latitudes

Abstract

WITHIN the past three years, whistlers have been heard consistently at a number of stations located on the polar side of the auroral zones. Certain characteristics of polar whistlers have been reported by Martin¹ for Scott Base (geomagnetic latitude 79.3° S.), by Ungstrup² for Godhavn (79.8° N.) and by Helliwell et al. ³ for Byrd Station (70.6° S.). In each case similarities to whistlers received at lower latitudes are noted, which lend support to Martin's suggestion that polar whistlers originate in lower latitudes and are then propagated into the polar regions by reflexion between the Earth and the lower ionosphere. The purpose of this communication is to describe observations showing that lightning sources in middle latitudes can give rise to whistlers heard at polar latitudes.