E. A. Sheina

Numerical simulation of a nonuniform dielectric inclusion in a waveguide aimed at reconstructing its permittivity

We consider numerical determination of the dielectric media parameters of inclusions in a waveguide of rectangular cross-section from the transmission coefficient. We develop and apply computer codes implementing the FDTD algorithm for nonstationary Maxwells equations with perfectly matched layer (PML) absorbing boundary conditions using the Berenger layout and estimate parameter ranges providing the prescribed accuracy for solving forward and inverse scattering problems for waveguides with inclusions.

Optimization of the boundary conditions and computational parameters for the FDTD solution of the inverse problem of reconstructing permittivity of a dielectric inclusion in a waveguide

Wave propagation in a waveguide of rectangular cross section with perfectly conducting wall containing an inhomogeneous dielectric insert in the form of a parallel-plane diaphragm with an inclusion is simulated numerically. The permittivity of the inclusion is a quantity to be restored from as little information about the scattered field as possible using FDTD numerical solution of Maxwells equations with nonlocal multimode scattering boundary conditions. The optimal number of higher-order evanescent waves and the size of the computational waveguide domain are found using the series of numerical experiments.

Absorbing boundary conditions for FDTD analysis of rectangular waveguide with non-uniform dielectric inclusions

When the finite-difference time-domain method is used for analysis of waveguide structures, incident waves are needed for calculating electromagnetic parameters and effective absorbing boundary conditions are required for terminating open waveguide structures.

Influence of standing waves on the solution of the inverse problem of reconstructing parameters of a dielectric inclusion in a waveguide

We consider numerical determination of the dielectric media parameters of inclusions in a waveguide of rectangular cross-section from the transmission coefficient. We develop and apply computer codes implementing the FDTD algorithm for numerical solution of the nonstationary Maxwell equations with perfectly matched layer (PML) absorbing boundary conditions using the Berenger layout. We estimate parameter ranges providing the necessary accuracy for solving forward and inverse scattering problems for waveguides with inclusions. Aposteriori estimate of the amplitude of higher-order evanescent waves is obtained and their influence on the choice of parameters of the numerical method is determined.

Neoclassical thermal conductivity in ICP plasma at low pressure

The plasma temperature in a new plasma source shows unusual behaviour at low pressures (about 1 mTorr) and high absorbed powers. In Ar plasma at pressures of about 1 mTorr, the electron temperature shows a pronounced maximum inside an electromagnetic accelerator, which is followed by a rapid drop at the boundary between the accelerator region and the main chamber. In this paper a neoclassical thermo-conductivity model based on the analysis of the electron trajectories is proposed to describe the sharp electron temperature profile. Quantitative agreement of the calculated temperature profile with the experiment is observed.