Self-excited surface plasmon-polaritons at the interface of counterstreaming plasmas

Surface plasma modes are coupled electromagnetic/electrostatic (plasmon-polariton) excitations of free electrons near the vacuum-plasma or plasma-plasma interface. The surface plasmon-polariton propagates along the surface plane and decays on both sides of the boundary. The effect of counterstreaming on the surface plasmon-polariton excitation is examined. It is shown that the two-stream instability can excite self-consistently the surface modes at the interface of two counterstreaming plasmas. The dispersion relation is derived and the exact numerical solutions are plotted for comparison to the excitations of a nonstreaming plasma-plasma interface. Such plasma models are of interest in electronic signal transmission, as well as in astrophysical applications and in beam-plasma experiments.