Time Reflection Coefficient Research Articles

Wave propagation through a moving plasma perturbation in a relativistic plasma

We consider wave propagation in a cold and isotropic relativistic plasma, in the presence of a moving density perturbation, which can be created by a particle bunch or by an intense laser pulse. We derive the space and time reflection coefficients and discuss the associated frequency shifts. This work could be useful for the development of radiation sources and new diagnostic techniques for laser and plasma acceleration experiments.

Transient analysis of two coupled horizontal wires over a real ground

Transient behaviour of two coupled wires immersed in a two-media configuration is analysed. The active wire is excited by a time-dependent voltage source. As the wires are identical, the symmetry of the configuration is expoited, and two coupled wires are considered as two single-wire problems. Each mode is represented by the corresponding space–time integral equation of the Hallen type. The effect of real ground is taken into account by the space–time reflection coefficient appearing within integral-equation kernels. The set of decomposed Hallen integral equations is solved by the direct time-domain finite-element technique, and the corresponding transient response is obtained. The computed numerical results are compared with the time-domain data obtained by solving the frequency-domain electric field integral equation for thin wires and with the aid of the Fourier transform approach. The mathematical model is applicable to an arbitrary ground, and numerical implementation and calculations are presented for lossless cases. Illustrative numerical results for transient current along the active and the parasitic wire are shown for the case of a perfectly conducting half-space and a dielectric half-space.