REAL RAY TRACING IN AN UNMAGNETIZED ABSORPTIVE IONOSPHERE.

The paper deals with the numerical investigation of real rays in an unmagnetized collisional ionospheric model, described by means of a single recombination Chapman layer with an exponential profile for the collision frequency. The presence of dissipation, leading to a complex dispersion relation, has caused grave difficulties in the past. This is due to the fact that complex index of refraction and group velocity do not vanish in real space; hence the height of reflection could not be determined. This is obviated hereby using a recent ray theory which extends Hamilton's equations to absorbing media, still using real space-time. Results of machine computations for various absorption conditions are graphically displayed. The most interesting result is the fact that absorption does not appreciably distort the ray path, even under severe conditions. This adds credibility to previously used heuristic approximations.