A statistical survey of ELF waves in a geostationary orbit

GEOS 2 is a geostationary satellite that was launched with a wave experiment. The data provided during its lifetime (∼ 3.5 years) constitute a unique set for the statistical study of electromagnetic and electrostatic waves at L = 6.6. The aim of this paper is to present maps of the average intensity of the electric and magnetic field. The location of the more intense emissions up to 4.6 kHz is shown as a function of local time and frequency. Such emissions are mainly composed of hiss, chorus and electron‐cyclotron harmonic (ECH) waves. Their locations were specified and compared with data from the OGO 5 and SCATHA satellites. In particular, this study highlights the characteristics of chorus emissions with a gap at half the electron gyrofrequency. It is also shown that global magnetic activity only slightly influences wave amplitude.