Propagation characteristics of oblique incidence terahertz wave through non-uniform plasma

The propagation characteristics of oblique incidence terahertz(THz) waves through non-uniform plasma are investigated by the shift-operator finite-difference time-domain(SO-FDTD) method combined with the phase matching condition.The electron density distribution of the non-uniform plasma is assumed to be in a Gaussian profile. Validation of the present method is performed by comparing the results with those obtained by an analytical method for a homogeneous plasma slab.Then the effects of parameters of THz wave and plasma layer on the propagation properties are analyzed. It is found that the transmission coefficients greatly depend on the incident angle as well as on the thickness of the plasma, while the polarization of the incident wave has little influence on the propagation process in the range of frequency considered in this paper. The results confirm that the THz wave can pass through the plasma sheath effectively under certain conditions,which makes it a potential candidate to overcome the ionization blackout problem.

Light propagation characteristics of turbulent plasma sheath surrounding the hypersonic aerocraft

The characteristics of light propagation through turbulent plasma sheath surrounding the hypersonic aircraft have been studied.The turbulent flow fields around a hypersonic aircraft are given by using the Navier–Stokes(NS) equations and k–ε turbulence model.Based on the distribution of flow field, refractive index and density of the plasma sheath for a blunt cone are discussed with different flight velocities and altitudes.The refractive index is mainly influenced by the electrons in the turbulent plasma sheath.The influence of different velocities and altitudes on the features of light propagation in the turbulent plasma sheath is analyzed.The results show that as the flight speed increases or the flight altitude decreases,the refractive index fluctuation becomes larger.It is also found that the refractive index fluctuation varies with the incident wavelength.This study shows how the characteristics of an optical beam propagating through plasma sheath are affected by the incident wavelength, flight velocities, and altitudes.

Analysis of the influence of sheath positions,flight parameters and incident wave parameters on the wave propagation in plasma sheath

The plasma sheath covering hypersonic vehicles has a significant effect on the propagation of electromagnetic waves.Based on the calculation of the flow field of a conical cylindrical,this work studies the propagation of electromagnetic waves in plasma sheath at L-band and Ku-band,and discusses the propagation characteristics in the head,side and tail of the sheath.The dielectric properties of plasma sheath are related to flight speed and altitude.A flight condition corresponds to a unique distribution of dielectric properties.For the conical cylindrical,the results show that flight speed is generally negatively correlated with the transmissivity of the plasma sheath.The reflection characteristics of electromagnetic waves at the L-band and Kuband when obliquely incident to the plasma sheath show a downward trend.When the frequency is increased to Ku-band,the propagation characteristics of electromagnetic waves in the plasma sheath are related to the position of the sheath.