Dipole antenna radiation in a compressible, anisotropic electron plasma overlying an imperfectly conducting half-space—lunar applications 2. Integration and results

摘要

The Fourier-Bessel integrals of part 1 (in this issue) are evaluated by the saddle-point method. By utilizing the arguments of ray optics, an algorithm is devised to find the saddle points by a numerical search procedure on dispersion surfaces. Reflection coefficients show a strong oscillatory structure as a function of frequency in the vicinity of the plasma frequency. This phenomenon is caused by rapid changes in ray convergence and by constructive-destructive interference of reflected modes. Branch-cut contributions yield lateral waves traveling along the dielectric boundary. The dominant lateral wave species is the modified extraordinary (MEX) mode launched by an acoustic-acoustic reflection. Other lateral waves are less important, and for these species, the position of the observer can go from the propagating zone to the shadow zone as the frequency is increased upward from the plasma frequency.