Direction finding of exit regions of magnetospheric VLF emissions at middle latitudes

• Published in: Advances in space research Vol. 20; no. 3; pp. 517 - 520
• Main Authors: Mullayarov, V.A, Kozlov, V.I
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.1997
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/S0273-1177(97)00722-9

The results of our experiments in measuring the exit points from the ionosphere of VLF emissions near Yakutsk ( Φ=62° N, λ=129° E) in February–April 1994 are presented. The measurements are made at frequencies 1,2–3,0 kHz through 0,2 kHz with a period of 20 s. It is found the zenith angles of exit points, as a rule, are less than 60°. Exit regions with small stable sizes of about 50 km are also detected at heights of the lower ionosphere. It points to ducted propagation of signals in the magnetosphere. The amplitude distribution of the signals has a maximum in the centre of the exit region. Depending on the wave disturbance level, different positions of the exit region are possible, but the region centres are usually near a zenith of the station.