Effect of negative ions on filamentation instability in collisionless three-fluid theory of plasmas with cold ion species

The growth rate of filamentation is examined analytically, as a function of the number density and the particle mass of negative ions, in the collisionless three-fluid theory of a plasma with cold ions. The growth rate dependence on the number density shows a qualitative change according to whether the pump intensity is below or above a critical level. In all cases of the pump intensity, the higher particle mass of negative ions means the weaker growth of filamentation. (C) 1996 American Institute of Physics.