Wake-field excitations in a multi-component dusty plasma

The wake-field excited by a test charge moving through a multicomponent dusty plasma is calculated by using the fluid as well as the Vlasov-Poisson model. It is shown that the ion-wake field may be oscillatory (Vt < CDA), constant (Vt ∝ CDA), or exponentially decreasing (Vt > CDA), depending upon the test charge velocity Vt relative to the dust acoustic speed CDA. Numerical results for the wake-field are presented for different test charge velocities. The work has relevance in space and astrophysical plasmas. (orig.)