IMPULSIVE AND TRANSIENT EXCITATION OF BOHM-GROSS WAVES IN A DISSIPATIVE PLASMA

Based on the resolution of the partial differential equation describin g the external excitation of the Bohm-Gross longitudinal wave, analyti cal expressions for causal responses of a dissipative macroscopic plas ma are derived. Both impulsive and harmonic solutions representing the spatial Green's functions of the radiation problem are given. These e xact responses of the plasma, expressed in terms of two-variable Lomme l functions, are then used to gain some better understanding of the ex citation and dynamics of the well-known thermal wave. Special attentio n is paid to the resonant excitation case. Intrinsic characteristics o f the secular behavior of the radiated signal are illustrated and anal yzed. It is shown that the proffered algebraic solutions constitute a generalization of previous results inferred from an asymptotic represe ntation of the Green's functions, or from the familiar steady state ha rmonic approach. (C) 1997 American Institute of Physics.