Decay of a magnetic-field-aligned Alfven wave into inertial and kinetic Alfven waves in plasmas

A simple description of three-wave decay interactions involving a magnetic-field-aligned dispersive Alfven wave (DAW) pump and two dispersive (either inertial or kinetic) Alfven waves that are propagating obliquely to the external magnetic-field direction in a uniform plasma is presented. The nonlinear dispersion relations and growth rates are obtained. The present results are useful for understanding the origin of constant-amplitude pump-driven nonthermal DAWs in ionospheric, magnetospheric, and heliospheric plasmas