Accession Number : ADA299615

Title :   Modeling of Ground Magnetic Signatures Associated with High Latitude Ionospheric Current Systems.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Gifford, Paul G.

PDF Url : ADA299615

Report Date : 10 SEP 1995

Pagination or Media Count : 143

Abstract : Due to their location, ionospheric currents are difficult to study directly. To gather information indirectly, magnetometers have been placed throughout the polar regions to measure perturbations in the geomagnetic field caused by the currents. The placement of these magnetometers has not been a coordinated effort, with the result that coverage is far from uniform and large gaps in the coverage exist. Understanding the abilities and limitations of the magnetometer networks to resolve details about changes in the magnetic field provides insight into the accuracy of the data. Discovering these abilities and limitations is the focus of this research. For use with ionospheric current system models, a simulation was made of a ground magnetometer. After validation of this simulation, it was used to verify Fukushima's theory on the cancellation of the ground magnetic signatures caused by the field aligned currents and Pedersen current. A distribution of the simulated magnetometers, patterned after the Scandinavian Magnetometer Array, proved successful in gathering information about traveling convection twin vortices. A global distribution of the magnetometers was tested with an ionospheric substorm model to find out what effects gaps in magnetometer coverage would have on the accuracy of data collected. It was found existing magnetometer networks do a reasonable job in returning accurate data, and the addition of more magnetometers to provide more uniform coverage did little to enhance the network's abilities.

Descriptors :   *MAGNETIC STORMS, *IONOSPHERIC DISTURBANCES, SIMULATION, GEOMAGNETISM, POLAR REGIONS, MAGNETIC FIELDS, ACCURACY, THESES, VORTICES, PERTURBATIONS, ELECTRIC CURRENT, IONOSPHERIC MODELS, DISTRIBUTION FUNCTIONS, MAGNETIC SIGNATURES, CONVECTION(ATMOSPHERIC), MAGNETOMETERS.

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE