On the relation between the red sprites and the transients in the ELF band

Abstract

Under favourable conditions sprites appear above large storms. Long continuing current in tens of ms in the parent +CG stroke radiates electromagnetic energy also in the Schumann resonance (SR) band. Optical and Extremely Low Frequency (ELF) observations at the Astronomical and Geophysical Observatory (AGO) near Modra are analyzed to find these two effects associated with +CG discharges. Since April 2007 dozens of sprites have been captured by automated all-sky TV system at AGO. A majority (77%) of the optical transient events are accompanied with the transients in the SR band. No ELF counterparts are found for 23% of the captured sprites. Our observations are compared with similar observations in Sopron and Nagycenk (NCK). Example of the optical frames, the associated ELF time plot and the Fourier as well as dynamic spectrum are presented for one of the events simultaneously observed at AGO and NCK.