Accession Number : AD0750741

Title :   Drift-Shell Splitting by Internal Geomagnetic Multipoles.

Descriptive Note : Rept. for Jan-May 72,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Hilton,Henry H. ; Schulz,Michael ; Roederer,Juan G.

Report Date : 25 SEP 1972

Pagination or Media Count : 42

Abstract : Computations on an 80-coefficient model of the earth's field illustrate the 'topography' of the magnetic equatorial surface (on which (B dot del B = O) and the geometry of the drift shells of geomagnetically trapped particles. Individual terms in the spherical-harmonic expansion (offset-dipole coordinates) of the geomagnetic scalar potential V(r, theta, phi) are either even or odd in cos theta, where theta = pi/2 denotes the dipole equator. Terms that (unlike the dipole) are even in cos theta tend to 'warp' the equatorial surface, but do not (in first order) distort particle drift shells radially nor split the drift shells of particles having different equatorial pitch angles. Azimuthally asymmetric terms that are odd in cos theta do cause shell splitting in first order. Shell splitting at large L values (neglecting deformation of the earth's field by the solar wind) is found to be dominated by the geomagnetic octupole. At L about = 1, shell splitting is strongly enhanced by the South American and South African anomalies. When combined with pitch-angle diffusion caused by atmospheric scattering, these results may be able to account for anomalous radial diffusion of inner-zone electrons. (Author)

Descriptors :   (*MAGNETOSPHERE, PARTICLE TRAJECTORIES), GEOMAGNETISM, CHARGED PARTICLES, DIFFUSION

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE