MAGNETOHYDRODYNAMIC SHALLOW WATER WAVES: LINEAR ANALYSIS

Journal Article · Thu Oct 01 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/2/1819· OSTI ID:21371860

Heng, Kevin ^[1]; Spitkovsky, Anatoly ^[2]

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1. Institute for Advanced Study, School of Natural Sciences, Einstein Drive, Princeton, NJ 08540 (United States)
2. Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States)

We present a linear analysis of inviscid, incompressible, magnetohydrodynamic (MHD) shallow water systems. In spherical geometry, a generic property of such systems is the existence of five wave modes. Three of them (two magneto-Poincare modes and one magneto-Rossby mode) are previously known. The other two wave modes are strongly influenced by the magnetic field and rotation, and have substantially lower angular frequencies; as such, we term them 'magnetostrophic modes'. We obtain analytical functions for the velocity, height, and magnetic field perturbations in the limit that the magnitude of the MHD analogue of Lamb's parameter is large. On a sphere, the magnetostrophic modes reside near the poles, while the other modes are equatorially confined. Magnetostrophic modes may be an ingredient in explaining the frequency drifts observed in Type I X-ray bursts from neutron stars.

• OSTI ID: 21371860
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 703; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
79 ASTRONOMY AND ASTROPHYSICS
FLUID MECHANICS
GEOMETRY
GRAVITY WAVES
HYDRODYNAMICS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICS
MECHANICS
MOTION
NEUTRON STARS
PERTURBATION THEORY
ROTATION
STARS
WATER WAVES