Accession Number : ADP006507

Title :   Oblique Heating of the Auroral Ionosphere by LF/MF Transmitters,

Corporate Author : ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)

Personal Author(s) : Cannon, P. S. ; Rycroft, M. J. ; Turunen, T.

Report Date : OCT 1990

Pagination or Media Count : 10

Abstract : The paper describes the generation of ELF signals due to oblique heating of the auroral ionosphere by signals from ELF modulated LF/MF radio transmitters. Apart from signals of natural origin, timing signals (six pips which occurred on the hour) were received. The pips of frequency 1 kHz, duration 1 05 ms and field strength -0.1 pT exhibit a favoured source location -1 50 km south-southeast of Sodankyla. The pips are shown to occur only when there is significant local magnetic activity and when the auroral electrojet is enhanced. The originating signals are demonstrated to be of Soviet origin and due to LF/MF broadcast transmitters several hundred kilometers away from the ELF source location. Various mechanisms which could account for a localised generation region far from the transmitters are discussed. The favoured mechanism involves in-phase heating due to two or more transmitters.

Descriptors :   *ELECTROMAGNETIC INDUCTION, *IONOSPHERIC DISTURBANCES, *RADIO SIGNALS, ELECTROJETS, HEATING, PHASE, RADIO TRANSMITTERS, REGIONS, ENERGY TRANSFER, EXTREMELY LOW FREQUENCY, LOW FREQUENCY, MEDIUM FREQUENCY.

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE