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The ionosphere plays an important role in the performance of critical civilian and defense communication systems. Perturbation studies of the ionosphere allow us to investigate the ionosphere and improve the performance of communications that rely on the ionosphere as well as develop new applications. A key instrument in ionospheric modification is the ionospheric heater, a powerful high frequency...
For many applications it is desirable to develop electron beam driven efficient sources of electromagnetic radiation producing the required power at beam voltages as low as possible. This trend is limited by space charge effects. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated...
Development of Mobile Ionospheric Heating sources (MIHs) would allow investigators to conduct needed research at different latitudes without building permanent and costly installations. As part of an Air Force Multi-University Research Initiative (MURI), the University of Maryland is designing a prototype of a powerful Radio Frequency (RF) source utilizing Inductive Output Tube (IOT) technology operating...
The resonant circuit in an Inductive Output Tube (IOT) extracts the kinetic energy of the modulated electron beam converting it to electromagnetic energy. For the application considered here, mobile low-frequency sources (5–10 MHz) for ionospheric heating, high efficiency is important, and thus class D operation is desired. The broad frequency range requires the circuit to be tunable, and the need...
The University of Maryland is developing a high power Radio Frequency (RF) source for use as a Mobile Ionospheric Heating Source (MIHS). This prototype will utilize Inductive Output Tube (IOT) technology operating in class-D amplifier mode using a grid-less electron gun. This paper will present a novel grid-less electron gun design, capable of producing annular beams with high currents in the range...
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