Ion beam generation at the plasma sheet boundary layer by kinetic Alfven waves

Journal Article · Tue Aug 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA08p10047· OSTI ID:5837827

Moghaddam-Taaheri, E; Goertz, C K; Smith, R A ^[1]

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1. Univ. of Iowa, Iowa City (USA)

The kinetic Alfven wave, an Alfven wave with a perpendicular wavelength comparable to the ion gyroradius, can diffuse ions both in velocity and coordinate spaces with comparable transport rates. This may lead to the generation of ion beams in the plasma sheet boundary layer (PSBL). To investigate the ion beam generation process numerically, a two-dimensional quasi-linear code was constructed. Assuming that the plasma {beta} (the ratio of plasma pressure to the magnetic pressure) varies from {beta} = 1 to {beta} << 1 across the magnetic field, the dynamics of the ion beam generation in the PSBL was studied. It was found that if your start with an ion distribution function which monotonically decreases with velocity along the magnetic field and a density gradient across the magnetic field, ions diffuse in velocity-coordinate space until nearly a plateau is established along the diffusion path. Depending on the topology of the magnetic field at the lobe side of the simulation system, i.e., open or closed field lines, the ion distribution function may or may not reach a steady state. If the field lines are open there, i.e., if the diffusion extends into the lobe, the double diffusion process may provide a mechanism for continuously transferring the ions from the central plasma sheet to the lobe. The authors comment on the effect of the particle loss on the establishment of the pressure balance in the plasma sheet.

• OSTI ID: 5837827
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A8; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
BEAMS
BOUNDARY LAYERS
CHARGED PARTICLES
CHARGED-PARTICLE TRANSPORT
COMPUTERIZED SIMULATION
DIFFUSION
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
FUNCTIONS
GEOMAGNETIC FIELD
HYDROMAGNETIC WAVES
ION BEAMS
IONS
LAYERS
MAGNETIC FIELDS
MAGNETOTAIL
MATHEMATICS
NUMERICAL SOLUTION
PLASMA SHEET
QUASILINEAR PROBLEMS
RADIATION TRANSPORT
SIMULATION
TOPOLOGY