Average spatial distributions of energetic particles in the midaltitude cusp/cleft region observed by Viking

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA05p05753· OSTI ID:5029230

Kremser, G; Lundin, R ^[1]

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1. Swedish Inst. of Space Physics, Kiruna (Sweden)

The cusp/cleft region provides an entrance for magnetosheath particles into the magnetosphere and a sink for magnetospheric particles. In addition, strong acceleration and/or scattering of particles takes place. The Swedish satellite Viking crossed this region at midaltitudes. Measurements from this spacecraft were used to determine the average spatial distributions of H{sup +} and He{sup ++} ions in the energy/charge range 2 keV/e {le} E/Q {le} 60 keV/e and of electrons with 7 keV {le} E {le} 97 keV. The data supply information on the structure of the midaltitude cusp/cleft region, the particle sources, and dynamical processes. Four different parts can be distinguished: (1) The cusp extends from about 76{degree} to 82{degree} invariant latitude (INL) and from 0800 to 1400 MLT. It is characterized by the presence of magnetosheath origin particles and important electron acceleration signatures. (2) A smaller region inside the cusp (77{degree}-82{degree} INL, 1000-1330 MLT) contains magnetosheath origin ions without electron acceleration. This is regarded as the cusp proper connected to the exterior cusp. (3) Poleward of the cusp magnetosheath origin ions are still present, but no magnetosheath electrons. This region is related to the plasma mantle. (4) Another region without magnetosheath origin ions but with strong electron acceleration extends equatorward of the cusp and probably constitutes part of the cleft, likely to be connected to the low-altitude boundary layer.

• OSTI ID: 5029230
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A5; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
BARYONS
BOUNDARY LAYERS
CHARGED PARTICLES
DISTRIBUTION
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HELIUM IONS
ION DENSITY
IONS
LAYERS
LEPTONS
MAGNETOSHEATH
MECHANICS
MORPHOLOGY
NUCLEONS
POLAR CUSP
PROTONS
SATELLITES
SPATIAL DISTRIBUTION