Reflection of Alfven waves at an open magnetopause

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

DOI:https://doi.org/10.1029/JA095iA04p04257· OSTI ID:5180799

Cao, F; Kan, J R ^[1]

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1. Univ. of Alaska, Fairbanks (United States)

Reflection of an Alfven wave incident on an open magnetopause form the magnetospheric side is examined. An open magnetopause, whose structure is different from the standard rotational discontinuity, is assumed to be a parameterized discontinuity with a nonzero normal field component. When an Alfven wave is incident on the open magnetopause, reflected and transmitted waves are generated. The emanating waves can be analyzed using linearized MHD conservation relations across the magnetopause, together with Snell's law. Under the assumption that the magnetic fields on the two sides of the open magnetopause are coplanar with the normal direction of the magnetopause, the governing equations are solved numerically. The results show that the electric fields of emanating Alfven waves depend mainly on the number density and the magnetic field jumps across the magnetopause. Under conditions representing the open magnetopause, it turns out that the open magnetopause behaves like a near perfect reflector. The corresponding reflection coefficient for the wave electric field can be approximated by R{sub E } = E{sup r}/E{sup i} {approx} -1 as has been deduced by Kan and Sun (1985) based on physical arguments. In other words, the solar wind flow is more or less unchanged by the loading effect of the Alfven wave incident on the magnetopause from the magnetospheric side. Therefore, under the assumptions of the model, the open magnetopause can be viewed as a constant voltage source.

• OSTI ID: 5180799
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A4; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
DATA ANALYSIS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC FIELDS
HYDROMAGNETIC WAVES
INTERACTIONS
MAGNETOPAUSE
MATHEMATICAL MODELS
MORPHOLOGY
NUMERICAL SOLUTION
REFLECTION
SOLAR ACTIVITY
SOLAR WIND