Propagation Properties of Terahertz Waves in a Time-Varying Dusty Plasma Slab Using FDTD

The complex dielectric permittivity of a dusty plasma, which contains an inhomogeneous electron density, charging response factor, and dust charging frequency caused by dust particles, is given to simulate the time-varying dusty plasma sheath. The recurrence field and current equations for terahertz (THz) wave propagation in the plasma are deduced and discretized using the auxiliary differential equation finite-difference time-domain (ADE-FDTD) method. The reflection, transmission, and absorption coefficients of a time-varying dusty plasma slab are calculated by using the ADE-FDTD method. The numerical results indicate that the reflection coefficients of the slab are easily affected by the rise time of the electron density. Besides, the absorption coefficients increase with the decrease in the rise time and working frequency as well as with the increase in the densities of electrons and dust particles. It is shown that THz waves may have potential applications in radio communications with a spacecraft at its re-entry into the atmosphere.