Using the linearized relativistic Vlasov-Maxwell equations,a generalized expression for the plasma conductivity tensor is derived.The dispersion relation for the O-mode in a relativistic degenerate electron plasma is ...Using the linearized relativistic Vlasov-Maxwell equations,a generalized expression for the plasma conductivity tensor is derived.The dispersion relation for the O-mode in a relativistic degenerate electron plasma is investigated by employing the Fermi-Dirac distribution function.The propagation characteristics of the O-mode（cut offs,resonances,propagation regimes,harmonic structure） are examined by using specific values of the density and the magnetic field that correspond to different relativistic dense environments.Further,it is observed that due to the relativistic effects the cut off and the resonance points are shifted to low frequency values,as a result the propagation regime is reduced.The dispersion relations for the non-relativistic and the ultra-relativistic limits are also presented.展开更多
In this study, the null-field boundary integral equation method （BIEM） and the image method are used to solve the SH wave scattering problem containing semi-circular canyons and circular tunnels. To fully utilize th...In this study, the null-field boundary integral equation method （BIEM） and the image method are used to solve the SH wave scattering problem containing semi-circular canyons and circular tunnels. To fully utilize the analytical property of Circular geometry, the polar coordinates are used to expand the closed-form fundamental solution to the degenerate kernel, and the Fourier series is also introduced to represent the boundary density. By collocating boundary points to match boundary condition on the boundary, a linear algebraic system is constructed. The unknown coefficients in the algebraic system can be easily determined. In this way, a semi-analytical approach is developed. Following the experience of near-trapped modes in water wave problems of the full plane, the focusing phenomenon and near-trapped modes for the SH wave problem of the half-plane are solved, since the two problems obey the same mathematical model. In this study, it is found that the SH wave problem containing two semi-circular canyons and a circular tunnel has the near-trapped mode and the focusing phenomenon for a special incident angle and wavenumber. In this situation, the amplification factor for the amplitude of displacement is over 300.展开更多
文摘Using the linearized relativistic Vlasov-Maxwell equations,a generalized expression for the plasma conductivity tensor is derived.The dispersion relation for the O-mode in a relativistic degenerate electron plasma is investigated by employing the Fermi-Dirac distribution function.The propagation characteristics of the O-mode（cut offs,resonances,propagation regimes,harmonic structure） are examined by using specific values of the density and the magnetic field that correspond to different relativistic dense environments.Further,it is observed that due to the relativistic effects the cut off and the resonance points are shifted to low frequency values,as a result the propagation regime is reduced.The dispersion relations for the non-relativistic and the ultra-relativistic limits are also presented.
基金Ministry of Science and Technology under Grant No.MOST 103-2815-C-019-003-E to the undergraduate studentthe NSC under Grant No.100-2221-E-019-040-MY3
文摘In this study, the null-field boundary integral equation method （BIEM） and the image method are used to solve the SH wave scattering problem containing semi-circular canyons and circular tunnels. To fully utilize the analytical property of Circular geometry, the polar coordinates are used to expand the closed-form fundamental solution to the degenerate kernel, and the Fourier series is also introduced to represent the boundary density. By collocating boundary points to match boundary condition on the boundary, a linear algebraic system is constructed. The unknown coefficients in the algebraic system can be easily determined. In this way, a semi-analytical approach is developed. Following the experience of near-trapped modes in water wave problems of the full plane, the focusing phenomenon and near-trapped modes for the SH wave problem of the half-plane are solved, since the two problems obey the same mathematical model. In this study, it is found that the SH wave problem containing two semi-circular canyons and a circular tunnel has the near-trapped mode and the focusing phenomenon for a special incident angle and wavenumber. In this situation, the amplification factor for the amplitude of displacement is over 300.
