Reflection Of Electromagnetic Pulse Research Articles

Numerical Analysis of the Effects Caused by Ground Reflection on Aperture Coupling

In order to analyze the influence of the near-ground reflection on aperture coupling, a full-scale model of metal shelter with a lossy ground was constructed. The rules of aperture coupling of the High-altitude Electromagnetic Pulse were researched, while the angle of incidence, the conductance and relative permittivity of the ground were changed respectively. Then the strength of electric field inside the shelter was computed and compared when the shelter was above on different topography. Studies show that the coupling electromagnetic energy strengthen with the incident angle of plane wave increasing. When the conductance and relative permittivity of the ground gain, the main crest of the electric field substantially keeps constant, while the second crest increases dramatically. Sea surface has the strongest reflection of electromagnetic pulse, followed by sand land, then the mud land. The reflection of wet land is much stronger than dry land.

Electromagnetic pulse reflection at self-generated plasma mirrors: Laser pulse shaping and high order harmonic generation

A thin layer of overdense plasma is created when an electromagnetic pulse interacts with a rapidly ionizing thin foil. This layer will reflect the incoming pulse, forming a so-called plasma mirror. A simple realistic model based on paired kinetic and wave equations is used to analytically describe the process of mirror formation and the reflection and transmission of the incident pulse. The model incorporates the exact description of the ionization process in the foil and the polarization and conduction currents that follow. The analytical description of the reflected and transmitted pulses as well as their dependence on foil parameters, and initial pulse amplitude and form are presented. Possible application and effectiveness of this process to improve laser pulse contrast are discussed. In the case of the linearly polarized incident pulse, harmonic generation occurs, that is absent in the case of the circular polarization. The spectra of the reflected pulses for different initial forms and amplitudes are studied.

FDTD modeling of transient scattering by subsurface targets

In this paper, a two-dimensional (2-D) finite-difference time-domain method (FDTD) scheme is used to simulate the transient scattering characteristics of buried objects, which are modeled by columns of arbitrary permittivities, conductivities, and sizes. The FDTD soil is modeled by isotropic, homogeneous and lossy media. The standing-traveling wave boundary condition (STWBC) that can simplify calculation and save CPU storage is used for modeling physical absorbers inside the FDTD computational domain. Reflection of electromagnetic pulses incident on a layered medium and transient scattering by the ground and an underground air square cylinder are computed. These results verify the validity of the FDTD scheme by comparisons with those shown in some references. Numerical results presented in the final part of this paper are desirable and meaningful, explicitly distinguishing echo waves stemming from the ground and the buried objects.

Reflection of electromagnetic pulses from inverted media

Reflection of electromagnetic pulses from inverted media

On one peculiarity of the reflection of electromagnetic pulses by a nonuniformly moving conducting medium

On one peculiarity of the reflection of electromagnetic pulses by a nonuniformly moving conducting medium

The reflection of electromagnetic pulses from jet streams†

Electromagnetic pulse reflection from a laminar, plane stratified jet stream is investigated, when the incident pulse is Gaussian amplitude modulated. It is seen that the pulse is delayed and distorted on reflection from the jet stream. Numerical results depicting the nature of the pulse after reflection are presented.

Distortion of electromagnetic pulses at totally reflecting layers

The plane-wave reflection of electromagnetic pulses from homogeneous and inhomogeneous layered media is discussed. Special attention is given to the case of total reflection which is characterized in the frequency domain by phase distortion without amplitude distortion. For this case it is shown that the waveform in the time domain undergoes a rather remarkable change.

The distortion of electromagnetic pulses undergoing total internal reflection in a stratified troposphere

The treatment of total internal reflection of electromagnetic pulses at the sharp boundary of two homogeneous half-spaces is extended to cover the case of total internal reflection in a stratified nonionized half-space. It is indicated that any inhomogeneity of the reflecting medium perturbs each harmonic spectral component of the reflected pulse in phase and amplitude as both the real and the imaginary parts of the reflection coefficient actually become functions of the frequency.