Behavior of hydrodynamic and magnetohydrodynamic turbulence in a rotating sphere with precession and dynamo action

Manuel I. Etchevest, Mauro Fontana, Pablo Dmitruk

Published 2022-05-06Version 1

The effect of precession in a rotating sphere filled with fluid was studied with direct numerical simulations, both in the incompressible hydrodynamics (HD) and magnetohydrodynamics (MHD) scenarios. In both cases the asymptotic state and its dependence with both rotating and precession frequency was analyzed. For the MHD case it was found that a retrograde precession was necessary to obtain self-sustaining dynamos, with a critical value ($\gamma_c=-3$) for the precession frequency, below which dynamo action was not maintained. It was also found that these correspond to small scale dynamos with a developed turbulent regime. Furthermore it is observed the presence of reversals of the magnetic dipole moment with greater waiting times between reversals for smaller precession frequencies.