Observing magnetospheric waves propagating in the direction of electron drift with Ekaterinburg Decameter Coherent Radar

Abstract

This paper deals with Pc5 magnetospheric pulsations featuring positive azimuthal wave numbers registered with the mid-latitude coherent decameter radar located near Ekaterinburg (EKB). The azimuthal wave numbers are determined using adjacent high time resolution beams directed toward the magnetic pole. Approximately 13 % of all steady waves registered with the radar propagate eastward. We have examined ten cases of wave observations with both small and high positive wave numbers, which occurred between April 2014 and March 2015. We performed a wavelet analysis of the data sets, estimated wavelength in radial direction for four cases, and determined meridional phase propagation direction. In three cases, the results are consistent with field line resonance behavior. However, in the majority of the studied events wave frequencies are considerably lower than those of field line resonance, which were derived from satellite data on magnetic field and particle density. These waves may be classed with the drift-compressional mode.

Keywords

• ULF waves
• radar
• magnetosphere