NONLINEAR DEMODULATION OF AN AMPLITUDE-MODULATED ELECTROMAGNETIC WAVE IN A PLASMA

Abstract

In this paper the authors have derived the expression for the electric vector when an amplitude-modulated electromagnetic wave propagates in a nonlinear dispersive medium. Demodulation is obtained in the case of a wave propagating in a nonlinear medium, whereas overmodulation has been obtained when the wave is reflected back in the free space from a plasma free-space interface. Some calculations have been performed in both cases and it has been found that the demodulation decreases with increasing electron density, with increasing index of modulation of the incident wave, and with increasing collision frequency. In the case of reflection the overmodulation is found to decrease with decreasing electron density, increasing index of modulation, and decreasing collision frequency inside the plasma. The calculated results have been presented in the form of tables in the Discussion.