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Energy transfers in dynamos with small magnetic Prandtl numbers |
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| Authors: | Rohit Kumar Mahendra K. Verma Ravi Samtaney |
| Affiliation: | 1. Department of Physics, Indian Institute of Technology, Kanpur, Indiarohitkr@iitk.ac.in;3. Department of Physics, Indian Institute of Technology, Kanpur, India;4. Mechanical Engineering, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia |
| Abstract: | We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due to the energy transfers from large-scale velocity field to large-scale magnetic field and that the magnetic energy flux is forward. The steady-state magnetic energy is much smaller than the kinetic energy, rather than equipartition; this is because the magnetic Reynolds number is near the dynamo transition regime. We also contrast our results with those for dynamo with Pm = 20 and decaying dynamo. |
| Keywords: | magnetic field generation dynamo energy transfers magnetohydrodynamic turbulence direct numerical simulation |