Analysis of propagation characteristics of Gaussian beams in turbulent plasma sheaths

Abstract

In this paper, the characteristics of Gaussian beam propagation through turbulent plasma sheath are studied. According to the generalized Huygens-Fresnel principle, the random phase screen is generated by power spectrum inversion method based on the fast Fourier transform. The random phase screen is used to simulate turbulence effect. The thickness of the plasma sheath is of about centimeter order of magnitude. Compared with the single fast Fourier transform algorithm, the double fast Fourier transform algorithm is not prone to under-sampling and can obtain good image results, even if the diffraction distance is 1 mm. Therefore, double fast Fourier transform algorithm is used for investigating the beam propagation between two phase screens. The turbulence effect of the plasma sheath surrounding a hypersonic vehicle is simulated by the multi-random phase screens. When the flight altitude is 45 km and the flight speed is 18 Mach, the intensity of refractive index fluctuation variance ranges from <inline-formula><tex-math id="M2">\begin{document}${10}^{ - 11} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20182169_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20182169_M2.png"/></alternatives></inline-formula> to <inline-formula><tex-math id="M3">\begin{document}$ {10}^{ - 14} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20182169_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20182169_M3.png"/></alternatives></inline-formula> indicated by analyzing the plasma flow field around the hypersonic vehicle. The characteristics of the Gaussian beam propagation through the turbulent plasma are numerically simulated. The results show that the refractive index fluctuation, wavelength and transmission distance are important factors affecting the Gaussian beam quality. The larger the refractive index variance, the more severe the spot dispersion and the more obvious the light intensity fluctuation. As wavelength is longer, the ability of the Gaussian beam to resist turbulence becomes stronger and the dispersion of the light spot and the intensity fluctuation are smaller. The beam distortion and the spot dispersion become more severe as the transmission distance is longer.

Evolution of Airy Beams in Turbulence Plasma Sheath

“…where λ is the wavelength, ρ is the local electron density, and G(λ) is the Gladstone-Dale constant, which is defined as follows [29,43]:…”

“…For example, Zang et al discussed the phase characteristics of the plasma laser signal and the information transmission characteristics in the shock tube [28], providing an important reference. In addition, only a few scholars have studied the transmission characteristics of Gaussian beams in turbulent plasma sheaths, and it was initially found that visible and near-infrared bands are more suitable [29,30]. However, there have been no published reports on Airy beams in plasma turbulence.…”

Propagation of Partially Coherent Flat-Topped Vortex Hollow Beams in Anisotropic Turbulent Plasma

“…Over the ensemble of the statistical realization of the random medium, we can write the equation as follows [29]: where J 0 is the zero-order Bessel function and D ψ (r 1 ′ − r 2 ′ ) is the wave structure function through anisotropic turbulent plasma, which is given in Equation (1). Now, substituting Equations ( 10) and (12) into Equation (11), we get…”

“…e presence of anisotropic turbulent plasma sheaths around the vehicles can have a strong inuence on the communication characteristics between the vehicles and radars. It can perturb communication and in some circumstances may lead to a disconnection [7,8].In recent years, the propagation of various laser beams in anisotropic turbulent plasma has been investigated extensively [9][10][11][12][13].…”

Spiral Spectrum of a Laguerre-Gaussian Beam Propagating in Anisotropic Turbulent Plasma

“…In 2017, Yang et al studied the bit error rate (BER) performance of free-space optical links under the influence of plasma turbulence [26]. Lyu et al studied the propagation characteristics of Gaussian beams in plasma turbulence based on the random phase screen method in 2019 [27]. Due to the anisotropy exhibited by the large-scale structure of turbulent vortices, on the basis of processing the experimental images of hypersonic turbulence [28], Li et al transformed the anisotropic von Ká rmá n spectrum to obtain the anisotropic power spectrum of the refractive index fluctuations of the hypersonic turbulence in 2016 [29].…”