### Abstract

We numerically solve the magnetic induction equation in a spherical shell geometry, with a kinematically prescribed axisymmetric flow that consists of a superposition of a small-scale helical flow and a large-scale shear flow. The small-scale flow is chosen to be a local analog of the classical Roberts cells, consisting of strongly helical vortex rolls. The large-scale flow is a shearing motion in either the radial or the latitudinal directions. In the absence of large-scale shear, the small-scale flow operates very effectively as a dynamo, in agreement with previous results. Adding increasingly large shear flows strongly suppresses the dynamo efficiency, indicating that shear is not always a favorable ingredient in dynamo action.

Original language | English |
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Article number | 425501 |

Journal | Journal of Physics A: Mathematical and Theoretical |

Volume | 49 |

Issue number | 42 |

DOIs | |

Publication status | Published - 26 Sep 2016 |

Externally published | Yes |

### Keywords

- dynamo
- dynamo quenching
- large-scale shear
- magnetic field
- rotation rate
- small-scale flow
- suppression

### ASJC Scopus subject areas

- Statistical and Nonlinear Physics
- Statistics and Probability
- Modelling and Simulation
- Mathematical Physics
- Physics and Astronomy(all)

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## Cite this

*Journal of Physics A: Mathematical and Theoretical*,

*49*(42), [425501]. https://doi.org/10.1088/1751-8113/49/42/425501