Controlled Artificial Generation of Ultra-Low-Frequency Hydromagnetic Waves in the Ionosphere and Magnetosphere
Final rept. 1 Jan 1975-28 Feb 1977
STANFORD UNIV CA STANFORD ELECTRONICS LABS
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This report summarizes theoretical and experimental work sponsored by the Defense Advanced Projects Agency at Stanford University through the Office of Naval Research Contract No. N00014-75-C-1095. The primary purpose of this work, which was conducted during the interval 1 January 1975 through 28 February 1977, was to investigate the possibility of obtaining a relatively inexpensive method for the controlled artificial generation of ultra-low-frequency ULF frequencies less than 5 Hz geomagnetic pulsations. Because of the great penetration of these signals in sea water, the controlled artificial source could conceivably be used as a transmitter to communicate with deeply submerged receivers at a low data rate. A second purpose of the work was to investigate the feasibility of using airborne loop antennas for airundersea communication at ULF. The following are the major conclusions of this work 1 The controlled artificial generation of ULF geomagnetic pulsations by the peninsula method, i.e., by the passage of a ULF-modulated electric current around a relatively nonconducting peninsula in the sea or in a large saline lake, is feasible and that further experiments, in particular, a fullscale ULF wave generation experiment, appear desirable. 2 The controlled artificial generation of ULF geomagnetic pulsations by the VLF method, i.e., by the injection of ULF-modulated VLF signals into the magnetosphere from a large ground-based VLF transmitter, appears possible, but further theoretical and experimental studies are required to clarify the generation mechanism.
- Radiofrequency Wave Propagation
- Radio Communications