Accession Number : ADA139317

Title :   Active Ionospheric Generation on ELF/VLF Waves.

Descriptive Note : Final rept. 23 Oct 82-22 Dec 83,

Corporate Author : SCIENCE APPLICATIONS INC MCLEAN VA

Personal Author(s) : Papadopoulos,K ; Chang,C ; Ko,K

PDF Url : ADA139317

Report Date : 09 Jan 1984

Pagination or Media Count : 31

Abstract : Our work during the past year on active ELF/VLF generation has produced major breakthroughs in the understanding of nonlinear interactions in a dissipating medium such as the ionosphere for the purpose of downconverting H.F. to ELF/VLF waves. A key result was the fact that the contrary to the conventional understanding of such processes, the presence of a dissipative medium lowers the threshold for complete decay and increases the downconversion efficiency over the one expected on the basis of the Manley rowe relations. Two codes were developed and optimized. (I) The first code named CMPOWER required as input a model of the ionospheric electron density and magnetic field, and the transmitter characteristics. It's output is the ELF/VLF signal as a function of the modulation frequency and distance from the HF facility. (II) The second named TWC (three wave coupling) is a nonlinear code, which includes dissipation and finite pump size effects. (Author)

Descriptors :   *Ionospheric disturbances, *Electric generators, *Plasma generators, *Nonlinear systems, *Frequency converters, *Down converters, Coupling(Interaction), Electron density, Interactions, Extremely low frequency, Transmitters, Very low frequency, Pumping, Magnetic fields, Dissipation, High frequency, Coding, Signals, Ionosphere, Facilities, Modulation, Waves

Subject Categories : Atmospheric Physics
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE