Energy relations of plasma waves in planar two-dimensional electron-ion plasmas

A derivation of the energy densities and power flows of plasma waves in a planar two-dimensional electron-ion plasma is presented through a simple approach. In this method, the response of an external current density introduced into the system is determined by a so-called dispersion function. The advantage of the dispersion function is that it yields not only the dispersion relations of both plasmon (high-frequency) and ion-acoustic (low-frequency) waves of the system, but expressions for the energy relations as well.