Finger instability in radiatively driven dusty plasmas

In this work the dynamics of a three-fluid plasma consisting of electrons, ions and charged dust particles are considered. The plasma is illuminated by a radiation field, which, through absorbtion, accelerates the dust particles, By direct acid Coulomb collisions the gained momentum is partially transmitted to electrons and ions. A steady state can be achieved by an external gravitational field acting against the radiation. After presenting the steady-state flow, linear perturbations of dynamical variables with the wave vector perpendicular to the radiation flux are considered. A Linear analysis is performed by reducing the full three-fluid description to a suitable one-fluid system of equations, assuming the plasma to be quasineutral and omitting plasma species separation. It is demonstrated that when the drag force between ions and dust particles is a decreasing function of their relative velocity, the steady state is unstable against the formation of parallel layered streams with high and low relative Row velocities, i.e., multiple current sheets. The temporal evolution of this instability is then investigated by means of numerical simulations in the framework of a complete three-fluid model. (C) 2000 American Institute of Physics. [S1070-664X(00)01212-X].