Rossby waves in ” shallow water ” magnetohydrodynamics
نویسندگان
چکیده
Aims. The influence of a toroidal magnetic field on the dynamics of Rossby waves in a thin layer of ideal conductive fluid on a rotating sphere is studied in the " shallow water " magnetohydrodynamic approximation for the first time. Methods. Dispersion relations for magnetic Rossby waves are derived analytically in Cartesian and spherical coordinates. Results. It is shown that the magnetic field causes the splitting of low order (long wavelength) Rossby waves into two different modes, here denoted fast and slow magnetic Rossby waves. The high frequency mode (the fast magnetic Rossby mode) corresponds to an ordinary hydrodynamic Rossby wave slightly modified by the magnetic field, while the low frequency mode (the slow magnetic Rossby mode) has new and interesting properties since its frequency is significantly smaller than that of the same harmonics of pure Rossby and Alfvén waves.
منابع مشابه
Magnetohydrodynamic Shallow Water Waves: Linear Analysis
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-Poincaré 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 substant...
متن کاملOn the propagation of oceanic waves driven by a strong macroscopic flow
In this work we study oceanic waves in a shallow water flow subject to strong wind forcing and rotation, and linearized around a inhomogeneous (non zonal) stationary profile. This extends the study [1], where the profile was assumed to be zonal only and where explicit calculations were made possible due to the 1D setting. Here the diagonalization of the system, which allows to identify Rossby a...
متن کاملWave analysis for different splittings of the shallow water equations on the beta-plane
The effects of operator splitting on the wave solutions of the linearized shallow water equations have been investigated in [Á. Havasi, Dispersion analysis of operator splittings in the linearized shallow water equations, in: I. Lirkov, S. Margenov, J. Wasniewski (Eds.), Large-Scale Scientific Computing: 5th International Conference, LSSC 2005, Sozopol, Bulgaria, June 6–10, 2005, in: Lecture No...
متن کامل11c.3 Comparison of Techniques for Isolating Equatorial Rossby Waves in Synoptic Studies
Equatorial wave modes have been an increasing source of interest in recent years. However, isolating these waves in the intricacies of unfiltered tropical data can be difficult. Numerous studies have used a range of bandpass time filters to isolate these waves (Kiladis and Wheeler 1995; Dickinson and Molinari 2002; Molinari et al. 2006, manuscript submitted to J. Atmos. Sci.; and others). On th...
متن کاملEffect of Rossby and Alfvén waves on the dynamics of the tachocline
To understand magnetic diffusion, momentum transport, and mixing in the interior of the sun, we consider an idealized model of the tachocline, namely magnetohydrodynamics (MHD) turbulence on a β plane subject to a large scale shear (provided by the latitudinal differential rotation). This model enables us to self-consistently derive the influence of shear, Rossby and Alfvén waves on the transpo...
متن کامل