Artificial Ionospheres for Communications

This paper suggests the utilization of an artificial ionosphere (artificial electron cloud) for RF communication. For convenience the presentation is given in two major parts. The first part is concerned with the general considerations associated with the generation, dynamics and other physical characteristics of the artificial ionospheres. It presents a general survey of the data and analysis from several experiments designed and performed expressly for obtaining critical engineering parameters required for the systematic development of these clouds as a propagation medium. These parameters include 1) chemical yield of contaminant, 2) thermal ionization efficiency, 3) upper atmosphere wind velocities, 4) wind shear, 5) ambipolar diffusion, 6) neutral diffusion, 7) solar photoionization probabilities, and 8) several decay processes including mutual neutralization, chemical consumption, electron attachment, recombination, etc. The effect of these processes upon the propagation capabilities of electron clouds is emphasized. Finally, some suggested improvements are offered for optimizing the artificial ionosphere propagation capability. The analytical model for cloud reflection, which is discussed in detail, is the spherically symmetric Gaussian electron distribution cloud. Cross-sectional cloud values as a function of time, including the maximum case, are discussed for this model. Calculations of cloud effectiveness for other reflective cases assuming various distribution functions, as well as one refractive case, are also presented. For the model discussed, the RF communications capability of the artificially generated ionosphere is presented. Since it is of first-order importance, the geometrical limitation of cloud generation altitude as a function of system communications range is considered.