Dispersive field line resonances on auroral field lines

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/95JA01553· OSTI ID:227147

Streltsov, A; Lotko, W ^[1]

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1. Dartmouth College, Hanover, NH (United States)

The formation of dispersive Alfven resonance layers is investigated using a three-dimensional, two-fluid, magnetically incompressible model, including electron inertia and finite pressure. The equations are solved in {open_quotes}box{close_quotes} geometry with uniform magnetic field bounded by perfectly conducting ionospheres. Field line resonance (FLR) is stimulated within a density boundary layer with gradient transverse to ambient B; a parallel gradient in the Alfven speed is also included. Numerical results show that the resonance amplitude is largest on the magnetic shell with eigenfrequency matching the frequency of the surface wave propagating on the density boundary layer. Efficient coupling between the resonant Alfven wave and surface wave produces a relatively narrow FLR spectrum, even when the driver is broadbanded. Effective coupling to the external driver occurs only for long-wavelength azimuthal modes. It is shown that the parallel inhomogeneity limits radiation of dispersive Alfven waves by the FLR. The results provide new insights into low-altitude satellite observations of auroral electromagnetic fields and the formation of discrete auroral arcs. 61 refs., 9 figs.

• OSTI ID: 227147
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A10 Vol. 100; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALFVEN WAVES
AURORAL ZONES
COMPUTERIZED SIMULATION
LONG WAVE RADIATION
OSCILLATION MODES
PLASMA FLUID EQUATIONS
THREE-DIMENSIONAL CALCULATIONS