Pitch angle and radial diffusion of MeV protons in the outer magnetosphere

Journal Article · Thu Apr 01 04:00:00 EST 1976 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA081i010p01737· OSTI ID:7285706

Scholer, M; Morfill, G

The latitude dependence of the field line-averaged pitch angle diffusion coefficient of 1-MeV protons in the magnetosphere has been calculated under the following assumptions: Scattering is due to gyroresonant interaction with a broad band spectrum of ion cyclotron waves, and the magnetospheric magnetic field model includes the internal dipole and the external solar wind compression as well as night side current sheet effects. In addition, calculations were performed in a model which simulates geomagnetic storm time ring currents. It could be shown that the power levels of normal quiet time magnetospheric wave activity are not sufficient to cause strong pitch angle scattering but that this situation may change during geomagnetic storms, as has indeed been observed. By using the field line-averaged pitch angle diffusion coefficient the associated radial diffusion coefficent kappa/sub perpendicular/ (either through gyroresonant interaction or through shell splitting) was calculated. It was shown that kappa/sub perpendicular/ was too small in the pseudotrapping region to compete with direct particle access and that it yielded values comparable with previous estimates due to other processes in the high-latitude closed drift shell region. In contrast to these other estimates, which involved sudden impluses and sudden commencements to provide the magnetic fluctuations, the wave-particle interaction picture developed here implies a steady radial diffusion at all times, temporal enhancements occurring during geomagnetically disturbed times. (AIP)

• Research Organization: Max-Planck Institut fur Physik und Astrophysik, Institut fur Extraterrestrische Physik, Garching, West Germany
• OSTI ID: 7285706
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 81:10; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BARYONS
BREMSSTRAHLUNG
CURRENTS
CYCLOTRON RADIATION
DIFFUSION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GEOGRAPHICAL VARIATIONS
GEOMAGNETIC FIELD
HADRONS
INCLINATION
LATITUDE EFFECT
MAGNETIC FIELDS
MAGNETIC STORMS
MAGNETOSPHERE
MEV RANGE
MEV RANGE 01-10
NUCLEONS
PLASMA SHEET
PROTONS
RADIATIONS
RING CURRENTS
SOLAR ACTIVITY
SOLAR WIND
VARIATIONS