The Equator-S magnetometer is very sensitive and has a sampling rate normal
ly of 128 Hz. The high sampling rate for the first time allows detection of
ELF waves between the ion cyclotron and the lower hybrid frequencies in th
e equatorial dawnside magnetosphere. The characteristics of these waves are
virtually identical to the lion roars typically seen at the bottom of the
magnetic troughs of magnetosheath mirror waves. The magnetospheric lion roa
rs are near-monochromatic packets of electron whistler waves lasting for a
few wave cycles only, typically 0.2 s. They are right-hand circularly polar
ized waves with typical amplitudes of 0.5 nT at around one tenth of the ele
ctron gyrofrequency. The cone angle between wave vector and ambient field i
s nearly always smaller than 1 degrees.