On the Possible Orig in of Internal (2 3 Hz) Modulation of Pulsating Auroras

Abstract

Data of three all sky cameras in Kiruna and Tjautjas (Sweden) were used for estimation of altitude of pulsating arc like forms and investigation of so called internal modulation (2 3 Hz) during the ON phase of a few second pulsations. It is found that for two closely spaced arcs, internal modulation took place only in the lowest arc. Based on this finding , an explanation is proposed due to the pulsations of anomalous resistance in the field-aligned current associated with a pulsating structure appart to the traditional mechanism of particle scattering by VLF waves.