A mathematical model of the structure and evolution of small-scale discrete auroral arcs

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

DOI:https://doi.org/10.1029/JA095iA10p17199· OSTI ID:5102814

Seyler, C E ^[1]

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1. Cornell Univ., Ithaca, NY (United States)

A three-dimensional fluid model which includes the dispersive effect of electron inertia is used to study the nonlinear macroscopic plasma dynamics of small-scale discrete auroral arcs within the auroral acceleration zone and ionosphere. The motion of the Alfven wave source relative to the magnetospheric and ionospheric plasma forms an oblique Alfven wave which is reflected from the topside ionoshere by the negative density gradient. The superposition of the incident and reflected wave can be described by a steady state analytic solution of the model equations with the appropriate boundary conditions. This two-dimensional discrete auroral arc equilibrium provides a simple explanation of arural acceleration associated with the parallel electric field. Three-dimensional fully nonlinear numerical simulations indicate that the equilibrium arc configuration evolves three-dimensionally through collisionless tearing and reconnection of the current layer. The instability evolves nonlinearly to produce complex transverse structure that may be the origin of the folds and curls observed to be associated with small-scale discrete arcs. At late times the plasma becomes turbulent having transverse electric field power spectra that tend toward a universal k{sup {minus}5/3} spectral form.

• OSTI ID: 5102814
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A10; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ALFVEN WAVES
ANALYTICAL SOLUTION
AURORAE
AURORAL ZONES
BOUNDARY CONDITIONS
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INHOMOGENEOUS PLASMA
INSTABILITY
IONOSPHERE
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
MORPHOLOGY
NONLINEAR PROBLEMS
PLANETARY IONOSPHERES
PLASMA
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
TEARING INSTABILITY
THREE-DIMENSIONAL CALCULATIONS