Plasma convection and ion beam generation in the plasma sheet boundary layer

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02382· OSTI ID:5188383

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

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

Because of the dawn-dusk ekectric field E{sub dd}, plasma in the magnetotail convects from the lobe toward the central plasma sheet (CPS). In the absence of space or velocity diffusion due to plasma turbulence, convection would yield a steady state distribution function f = V{sup {minus}2/3}g(v{sup 2}V{sup 2/3}), where V is the flux tube volume. Starting with such a distribution function and a plasma beta which varies from {beta} > 1 in the CPS to {beta} {much lt} 1 in the lobe, the authors study evolution of the ion distribution function considering the combined effects of ion diffusion by kinetic Alfven waves (KAW) in the ULF frequency range (1-10 mHz) and convection due to E{sub dd} {times} B drift in the plasma sheet boundary layer (PSBL) and outer central plasma sheet (OCPS). The results show that during the early stages after launching the KAWs a beamlike ion distribution forms in the PSBL and at the same time the plasma density and temperature decrease in the OCPS. Following this stage, ions in the beams convect toward the CPS resulting in an increase of the plasma temperature in the OCPS. They also discuss the effects on the polytropic index {gamma} by simultaneous convection and wave-induced diffusion, both in the PSBL and CPS. They find that {gamma} is less than the adiabatic value ({gamma}{sub ad} = 5/3) in the OCPS but approaches the adiabatic value in the CPS and in the PSBL.

• OSTI ID: 5188383
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:A2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MAGNETOTAIL
ION BEAMS
PLASMA DRIFT
ALFVEN WAVES
CONVECTION
DISTRIBUTION FUNCTIONS
ELECTRIC FIELDS
MATHEMATICAL MODELS
PLASMA DENSITY
PLASMA SHEET
STEADY-STATE CONDITIONS
TURBULENCE
BEAMS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY TRANSFER
FUNCTIONS
HEAT TRANSFER
HYDROMAGNETIC WAVES
MASS TRANSFER
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena