GEOMAGNETIC FIELD PERTURBATIONS DUE TO TRAPPED PARTICLES

Technical Report · Sat Apr 01 04:00:00 EST 1961

OSTI ID:4843467

Apel, J A

Particles trapped in a magnetic dipole field cause two distinct magnetic effects; (i) the gyration about the lines of force gives rise to a magnetization current which produces a positive perturbation interior and exterior to the trapped particle region; and (ii) the particles drift in azimuth and the resultant ring current decreases the driving field interior to the trapping region and increases it to the exterior. At the dipole center this effect is opposite to and three times as large as the diamagnetic effect (i), Explicit expressions are derived for the current and the perturbed field which would be observed as one progressed radially outward in the equatorial plane through the outer radiation belt. A maximum current density of about 10/sup -8/ amp/m/sup 2/ flows in the vicinity of 30,000 km geocentric distance. The total current is of the order of 5 x 10/sup 6/ amp. At the point of greatest particle concentration, taken as 5 x 10/sup 6/ electrons per cubic meter at 25,000 km, the magnetic field anomaly is of the order of --100 to --250 gamma, depending on how sharply defined is the inner edge of the radiation belt. With the help of these results, the "magnetic signature" of any reasonable trapped particle distribution can be synthesized provided the gradient of the total field thus obtained is nowhere positive. The calculations appear capable of explaining the Explorer VI results in terms of a radiation belt of limited radial extent, in the vicinity of 40,000 km. It appears difficult to explain the "fine structure" at 21,000 km in the Lunik I results, but the gross behavior of the magnetic field is fairly well reprcduced. The magnitudes of the perturbations differ by a factor of 8, however. (auth)

• Research Organization: Maryland. Univ., College Park
• NSA Number: NSA-15-028311
• OSTI ID: 4843467
• Report Number(s): AFCRL-420; AD-254337
• Country of Publication: United States
• Language: English

Related Subjects

COSMIC RADIATION
CURRENTS
DIPOLES
DISTURBANCES
EARTH
EXPLORER SATELLITES
LEVELS
MAGNETIC FIELDS
MOTION
PHYSICS
RADIATION BELTS
SATELLITES
SPACE FLIGHT
SPACE VEHICLES
TURBULENCE