Download or read book Controlled Artificial Generation of Ultra-Low-Frequency Hydromagnetic Waves in the Ionosphere and Magnetosphere written by O. G Villard (Jr) and published by . This book was released on 1978 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 air/undersea 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.