Abstract: | Longitudinal plasma oscillations under the action of an external homogeneous time dependent electric field are examined with regard to the stability of the plasma. The basic model is an infinitely extended collisionless quasineutral two-component plasma. Starting from the linearized Vlasov equation dispersion relations are derived and discussed. It is shown that for an isothermal two-component plasma instabilities are possible, and limites for the area of instability are given. Further a second method of solution starting from an integral equation for the internal electric field is developed. The equivalence of both methods is shown by means of special cases. |