Radiation of Long Electromagnetic Waves by a Modulated Electron Beam in the Ionosphere

摘要

Pulsed electron beams in the ionosphere radiate electromagnetic energy and, therefore, might work as wireless virtual antennas. Such virtual antennas would be most useful at low frequencies because small or moderate-size wire antennas work well at high frequencies. Natural beams radiate energy that propagates down through the ionosphere, but no experiment has used a man-made electron beam to produce radiation at the modulation frequency or its harmonics, and detected that radiation on the ground. The present report addresses the feasibility of such an experiment, and suggests preferred configurations. Motivated by communications applications, which require good time availability, it considers only phenomena, such as the triggering plasma of instabilities or guidance in transient ionospheric ducts. Keywords include: Cerenkov radiation, ELF, Long wavelength communication, Low-frequency Communications, and Modulated electron beams.