One-dimensional particle simulation of wave propagation and generation of second harmonic waves in a composite of plasma and metamaterial

Abstract

One-dimensional electromagnetic particle simulations are performed with the combination of the overdense plasma and the negative-permeability state (metamaterial). Transverse electromagnetic waves enter the plasma-metamaterial composite, and the waves propagate in it with a negative phase velocity and a positive group velocity. We confirm that the plasma-metamaterial composite has a negative refractive index. The dispersion relation of the composite has the propagation band under the plasma frequency, and we confirm this band by theoretical calculations with the kinetic effects and by particle simulations. When the phase velocity approaches the thermal velocity of the electrons, we find the damping of the transverse wave in the propagation band. The propagating transverse waves generate the propagating second harmonic waves throughout the composite. The intensities of the second harmonic waves are enhanced because the fundamental frequency waves are efficiently injected into the overdense plasma with the metamaterial since the refractive index is not imaginary but real with negative values.