Quasi-linear theory of the ion-beam acoustic instability in the Earth's magnetotail plasma

Broadband electrostatic noise (BEN) as one of the most interesting phenomena occurring in the plasma sheet region of the Earth's magnetotail is investigated. The quasi-linear theory should be a good basis for studying the generation of BEN and its correlations with ion beams. Because after a short time interval the ion-beam acoustic instability becomes the dominant one in the dynamics of the ion beam-plasma sheet boundary layer-system an attempt is made to use the quasi-linear theory for studying the steady state of the system after ion-beam acoustic instability has saturated