Birkeland currents in an anisotropic, magnetostatic plasma

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA03029· OSTI ID:5509334

Birmingham, T J ^[1]

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1. NASA Goddard Space Flight Center, Greenbelt, MD (United States)

An expression for the parallel current density is derived for a plasma characterized by negligible bulk flow (magnetostatic) velocity and a two-component (anisotropic) pressure tensor by expanding the equilibrium Vlasov equation for each species in the adiabatic parameter until such point as a nonvanishing moment j{sub {parallel}} = {integral} d{sup 3} vv{sub {parallel}} is identified. The result is a nonlocal one: it relates j{sub {parallel}} at one point s along a field line to j{sub {parallel}} at another (reference) point s{sub 0} plus an integral function of the pressure and magnetic field between them. It is a generalization and elaboration of results obtained by Bostrom (1975), Heinemann (1990), and Heinemann and Pontius (1991). The expression could have been obtained by integrating the current continuity equation with {minus}{del} {times} j{sub {perpendicular}} as a source term and j {sub {perpendicular}} given by perpendicular momentum balance. The authors explicitly show the equivalency. The widely used Vasyliunas (1970) equation follows when P{sub {perpendicular}} is set equal to P{sub {parallel}} and s and s{sub 0} are taken to be at the ionosphere and the equator. An extended discussion of the relationship of results derived here to others in the literature is carried out in an effort to bring unity and perspective to this problem area.

• OSTI ID: 5509334
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A4; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ADIABATIC PROCESSES
ANISOTROPY
AURORAL ZONES
CURRENT DENSITY
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ELECTRODYNAMICS
GEOMAGNETIC EQUATOR
INTERACTIONS
IONOSPHERE
MAGNETIC FIELD CONFIGURATIONS
MASS TRANSFER
PLANETARY IONOSPHERES
PLASMA DRIFT