Modulated Rotating Waves in the Magnetised Spherical Couette System

  title={Modulated Rotating Waves in the Magnetised Spherical Couette System},
  author={F. Garcia and Martin Seilmayer and Andr{\'e} Giesecke and Frank Stefani},
  journal={J. Nonlinear Sci.},
We present a study devoted to a detailed description of modulated rotating waves (MRW) in the magnetized spherical Couette system. The set-up consists of a liquid metal confined between two differentially rotating spheres and subjected to an axially applied magnetic field. When the magnetic field strength is varied, several branches of MRW are obtained by means of three dimensional direct numerical simulations (DNS). The MRW originate from parent branches of rotating waves (RW) and are… 
Chaotic wave dynamics in weakly magnetized spherical Couette flows.
Direct numerical simulations of a liquid metal filling the gap between two concentric spheres are presented and a rich variety of flow features, both in terms of spatial symmetry and temporal dependence, is obtained.
Modulated rotating waves and triadic resonances in spherical fluid systems: The case of magnetized spherical Couette flow
The existence of triadic resonances in the magnetized spherical Couette system is related to the development of modulated rotating waves, which are quasiperiodic flows understood in terms of
Dynamic transitions of the magnetized spherical Couette flow between its base state and the return flow instability
The transition between the stable base state of the magnetized spherical Couette (MSC) flow and the return flow instability is experimentally investigated. The experiments are conducted using an MSC
Fluid Dynamics Experiments for Planetary Interiors
Understanding fluid flows in planetary cores and subsurface oceans, as well as their signatures in available observational data (gravity, magnetism, rotation, etc.), is a tremendous interdisciplinary
Triskels and Symmetries of Mean Global Sea-Level Pressure
The evolution of mean sea-level atmospheric pressure since 1850 is analyzed using singular spectrum analysis. Maps of the main components (the trends) reveal striking symmetries of order 3 and 4. The
On the annual and semi-annual components of variations in extent of Arctic and Antarctic sea-ice
The time series (1978-2022) of northern hemisphere ( NHSI ) and southern hemisphere ( SHSI ) sea-ice extent are submitted to singular spectral analysis ( SSA ). The spectral components are analyzed
A strong link between variations in sea-ice extent and global atmospheric pressure?
Abstract. Abstract. This paper reports spectral analyses, using Singular Spectral Analysis, of variations of the Arctic and Antarctic sea-ice extents (SI), and of the atmospheric surface pressure
Experimental investigation of the return flow instability in magnetized spherical Couette flows
We conduct magnetic spherical Couette (MSC) flow experiments in the return flow instability regime with GaInSn as the working fluid, and the ratio of the inner to the outer sphere radii $r_{\rm


Continuation and stability of rotating waves in the magnetized spherical Couette system: secondary transitions and multistability
The study reveals several regions of multistability of waves with azimuthal wavenumber, and several transitions to quasi-periodic flows, i.e modulated rotating waves.
Rotating spherical Couette flow in a dipolar magnetic field: experimental study of magneto-inertial waves
The magnetostrophic regime, in which Lorentz and Coriolis forces are in balance, has been investigated in a rapidly rotating spherical Couette flow experiment. The spherical shell is filled with
Instabilities in magnetized spherical Couette flow.
Three-dimensional numerical simulations of the flow of an electrically conducting fluid in a spherical shell when a magnetic field is applied show that instabilities arising from the presence of boundaries present striking similarities with the magnetorotational instability (MRI).
Continuation and stability of convective modulated rotating waves in spherical shells.
Newton-Krylov continuation allows us to obtain unstable MRW that cannot be found by using only time integrations, and identify regions of multistability, and it is shown how they become stable in a small Rayleigh-number interval, in which two branches of traveling waves are also stable.
Transitions in a magnetized quasi-laminar spherical Couette Flow
First results of a new spherical Couette experiment are presented. The liquid metal flow in a spherical shell is exposed to a homogeneous axial magnetic field. For a Reynolds number Re=1000, we study
Modes and instabilities in magnetized spherical Couette flow
Abstract Several teams have reported peculiar frequency spectra for flows in a spherical shell. To address their origin, we perform numerical simulations of the spherical Couette flow in a dipolar
Zonal shear and super-rotation in a magnetized spherical Couette-flow experiment.
The direct measurements of zonal velocity give a nice illustration of Ferraro's law of isorotation in the vicinity of the inner sphere, where magnetic forces dominate inertial ones.
Dynamic domains of the Derviche Tourneur sodium experiment: Simulations of a spherical magnetized Couette flow
The Derviche Tourneur Sodium experiment, a spherical Couette magnetohydrodynamics experiment with liquid sodium as the medium and a dipole magnetic field imposed from the inner sphere, recently
Helical magnetorotational instability in a Taylor-Couette flow with strongly reduced Ekman pumping.
This paper describes the observation of the HMRI in an improved Taylor-Couette setup with the Ekman pumping significantly reduced by using split end caps, and concludes that the observed HMRI represents a self-sustained global instability rather than a noise-Sustained convective one.
Magnetic spherical Couette flow in linear combinations of axial and dipolar fields
We present axisymmetric numerical calculations of the fluid flow induced in a spherical shell with inner sphere rotating and outer sphere stationary. A magnetic field is also imposed, consisting of