Stability and gravitational effects on surface dust-acoustic waves in self-gravitating semi-bounded dusty plasmas

Abstract

The stable conditions and gravitational effects on the surface dust-acoustic wave are investigated in self-gravitating semi-bounded dusty plasmas. The dispersion relation of the surface dust-acoustic wave is obtained by the plasma dielectric function with the specular reflection boundary condition. It is shown that the surface dust-acoustic wave become unstable for any values of the wave number when 1/2 <= (omega(J)/omega(pd))(2) <= 1. However, when (omega(J)/omega(pd))(2) > 1 or (omega(J)/omega(pd))(2) < 1/2, the Jeans instability does not occur for the domain of the wave number k(z)lambda(D)> (omega(J)/omega(pd))\[(omega(J)/omega(pd))(2)-1]/[2(omega(J)/omega(pd))(2)-1]\(1/2). It is also found that the phase velocity of the, surface wave decreases with increasing Jeans frequency.