Animation Gallery
Blocked convection (2004) Boussinesq convection in a plane layer rotating about a vertical axis. A circular region at the upper boundary has been insulated. After a time, the convection relaxes to a new state in which the rest of the surface compensates for the thermal flux reduction in the circular area. The animation shows the temperature fluctuations near the upper boundary. Light and dark tones correspond respectively to hot and cold fluid. Simulations by F. Cattaneo, P. Fischer & A. Obabko 

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Cylindrical Couette flow (2005) Axisymmetric flow between two rotating coaxial cylinders. The rotation rates of the inner and outer cylinders are chosen so that the angular velocity increases inwards, but the angular momentum increases outwards (Rayleigh stable regime). The animations show the azimuthal vorticity for two cases: one with lids rotating at he rate of the outer cylinder, and one in which the horizontal plates are made up of two rings rotating at angular velocities intermediate between those of the inner and outer cylinders. In both cases the inner cylinder is on the left. Simulations by F. Cattaneo, P. Fischer & A. Obabko 

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MagnetoRotational Instablity (2005) Magnetically unstable cylindrical Couette flow. Although the basic flow is Rayleigh stable it is linearly unstable to the MagnetoRotational Instability. The animation shows the radial flux of (axial) angular momentum. The two colours correspond to the transport by hydrodynamic (orange) and hydromagnetic (purple) fluctuations. Simulations by F. Cattaneo, P. Fischer & A. Obabko 

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MagnetoRotational Instability (2005) Magnetically unstable cylindrical Couette flow. Although the basic flow is Rayleigh stable it is linearly unstable to the MagnetoRotational Instability. The animation shows the radial flux of (axial) angular momentum. Simulations by F. Cattaneo, P. Fischer & A. Obabko


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MagnetoRotational Instability (2005) Magnetically unstable cylindrical Couette flow. Although the basic flow is Rayleigh stable it is linearly unstable to the MagnetoRotational Instability. The animation shows the regions of high magnetic dissipations (square current). Simulations by F. Cattaneo, P. Fischer & A. Obabko


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MagnetoRotational Instability (2005) Axisymmetric flow between two rotating coaxial cylinders. The rotation rates of the inner and outer cylinders are chosen so that the angular velocity increases inwards, but the angular momentum increases outwards. Although the basic flow is Rayleigh stable it is linearly unstable to the MagnetoRotational Instability. The animations show the fluctuations in azimuthal velocity (orange) and magnetic field (blue). The inner cylinder is on the left Simulations by F. Cattaneo, P. Fischer & A. Obabko 

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2.5 Dimensional Dynamos (2003) 2.5dimensional dynamos are driven by velocities that have three directional components but only depend on two spatial dimensions, (x,y), say. The animation on the left shows the "vorticity field" for one such dynamos in the xy plane. The animation on the right shows the corresponding magnetic field. Simulations by F. Cattaneo & S. Tobias


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ShearMagnetic Buoyancy Systems
(2004) The animation on the left shows the generation of toroidal magnetic field by a localized velocity shear. The "flux tubes" become unstable to a magnetic buoyancy instability and rise. The animation on the right show a similar system that is capable of sustained dynamo action, i.e. the magnetic field is maintained even if the weak poloidal field is removed. Simulations by N. Brummell, F. Cattaneo & K. Cline


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Boussinesq Convection (2002) Boussinesq convection in a plane layer with large aspect ratio (20x20x1). The animation shows the temperature fluctuations near the upper boundary. Light and dark tones correspond respectively to hot and cold fluid. The rapidly evolving cellular pattern is typical of convection at high Rayleigh numbers. Simulations by F. Cattaneo


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Convective Dynamos &
MagnetoConvection (2004) Convection in an electrically conducting fluid. In the animation on the left the convection is capable of dynamo action and generates a highly intermittent magnetic field. On the right a vertical magnetic field is externally imposed with a strength sufficient to alter significantly the convective pattern. In both cases the visualization is a volume rendering of the regions of strong field. Simulations by F. Cattaneo & T. Emonet 

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Convective Dynamos (2004) Detail of a magnetic flux feature generated by dynamo action driven by convection. The animation shows the evolution of magnetic fluctuations near the upper surface. Light and dark tones correspond to magnetic fluctuations with up and down orientation respectively. The magnetic feature is located near a cellular corner. Simulations by F. Cattaneo


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Fast Dynamos (2004) Streamline pattern for the GallowayProctor flow. The colors correspond to up and down flows respectively. The animation on the right shows the corresponding magnetic eigenfunction (exponential growth removed). Simulations by F. Cattaneo 

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