Accession Number : AD0633604

Title :   A MATHEMATICAL APPROXIMATION TO THE GEOMAGNETIC FIELD.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Wiley,Robert Earl

Report Date : MAR 1966

Pagination or Media Count : 101

Abstract : An attempt was made to form a mathematical model for calculating the geomagnetic field using fewer terms than presently used in spherical harmonic expansion models. The model was to be made up of pairs of magnetic monopoles. It was found that at least four pairs of monopoles would be needed to produce a satisfactory model. The initial data used for fitting the four pair of monopoles was the geomagnetic field as calculated by a spherical harmonic expansion using the Jensen and Cain coefficients. Emphasis was given to fitting the South Atlantic Anomaly. The root-mean-square error for this region was 1.3 x 10 to the -2 gauss while the overall root-mean-square error was 3.4 x 10 to the -2 gauss. Comparison of the errors of the monopole model with the errors of the Jensen and Cain coefficients indicates that the root-mean-square error for the monopole model is larger than that of the Jensen and Cain coefficients. Additionally, it was found that the monopole model calculations were only 1/3 faster than the spherical harmonic expansion instead of the desired 1/2 or more reduction in calculation time. (Author)

Descriptors :   (*GEOMAGNETISM, MATHEMATICAL MODELS), MAGNETIC FIELDS, SPECIAL FUNCTIONS(MATHEMATICAL), LEAST SQUARES METHOD

Subject Categories : Geomagnetism
      Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE