Suicidal and parthenogenetic dynamos. (Q2776179)

The main purpose of the work is to demonstrate the dynamo effect. An electrically conducting, viscous and incompressible fluid that is imbedded inside of a spherical body is surrounded by a non-conducting fluid. The magnetic diffusivity, kinematic viscosity and mass density are considered as constant. Using standard MHD equations, the authors perform numerical studies of laminar flows in a rotating frame. Investigations are done for the case where an external body force is included. The stationary solution of the problem is found when the magnetic flux density and angular velocity are equal to zero. Depending on the external body force, one or two stable steady solutions may exist. It is found that two stable steady solutions differ in the distribution of energy into poloidal and toroidal motions, but their total kinetic energies differ only slightly. Problems of dynamo generation are examined for the above steady flow when a magnetic field is included. It is shown that dynamics of a system with interaction of magnetic field and flow motion can totally differ from the behavior obtained in the kinematic model. For low magnetic Reynolds numbers, the growing magnetic field can destroy the dynamo property of motion, but at sufficiently high magnetic Reynolds numbers a dynamo may be generated. Destroying of a dynamo occurs when more than one hydrodynamically stable states of system are stable or unstables with respect to magnetic perturbations. The evolution of magnetic energy and kinetic energy is examined for different system parameters.NEWLINENEWLINEFor the entire collection see [Zbl 0973.00055].