High energetic electrons and electron cyclotron waves and their harmonics in the polar cusp.

The most characteristic features of the wave spectra measured in the polar cusp found by Interball 1 and Polar satellites and confirmed by Cluster are the broad band emissions with maxima at the lower hybrid, around electron cyclotron and its harmonics frequencies. Interball 1 and its companion Magion 4 sometimes registered emissions with extremely high intensity in these frequencies ranges. These waves correlate with strong fluxes of high energetic electrons often observed within the polar cusp by Interball 1 and Magion 4 as well as by Polar satellites. Cluster measurements give new insight of these emissions. The observations of electron cyclotron and their harmonics gathered on Magion 4 and Cluster satellites associated with strong fluxes of energetic electrons will be presented. Short discussion of the possible generation mechanism, such as 'fan' instability, will be added