Magnetic field generation by intermittent convection

Abstract

Magnetic field generation in three-dimensional Rayleigh-Bénard convection of an electrically conducting fluid is studied numerically by fixing the Prandtl number at $P=0.3$ and varying the Rayleigh number (Ra) as a control parameter. A recently reported route to hyperchaos involving quasiperiodic regimes, crises and chaotic intermittent attractors is followed, and the critical magnetic Prandtl number ($P_m^c$) for dynamo action is determined as a function of Ra. A mechanism for the onset of intermittency in the magnetic energy is described, the most beneficial convective regimes for dynamo action in this transition to weak turbulence are identified, and the impact of intermittency on the dependence of $P_m^c$ on Ra is discussed.

17 pages, 6 figures

References in corpus (6)

• A Multiscale Dynamo Model Driven by Quasi-geostrophic Convection
• Bi-stability in turbulent, rotating spherical Couette flow
• Convective dynamo action in a spherical shell: symmetries and modulation
• Convection-driven kinematic dynamos at low Rossby and magnetic Prandtl numbers: single mode solutions
• Intermittency in spherical Couette dynamos
• Route to hyperchaos in Rayleigh-Benard convection

Cited by in corpus (3)

• Magnetic field generation by pointwise zero-helicity three-dimensional steady flow of incompressible electrically conducting fluid
• Transition to chaos and magnetic field generation in rotating Rayleigh-Bénard convection
• What makes a steady flow to favour kinematic magnetic field generation: A statistical analysis