Quantification of the velocity and magnetic field reversals in dynamo remains an interesting challenge. In this paper, using group-theoretic analysis, we classify the reversing and non-reversing Fourier modes during a dynamo reversal in a Cartesian box. Based on odd-even parities of the wavenumber indices, we categorise the velocity and magnetic Fourier modes into eight classes each. Then, using the properties of the nonlinear interactions in magnetohydrodynamics, we show that these 16 elements form Klein 16-group Z 2 × Z 2 × Z 2 × Z 2. We demonstrate that field reversals in a class of Taylor-Green dynamo, as well as the reversals in earlier experiments and models, belong to one of the classes predicted by our group-theoretic arguments.
Bibliographical noteKAUST Repository Item: Exported on 2022-06-03
Acknowledged KAUST grant number(s): K1052
Acknowledgements: We are thankful to Abhishek Kumar for extensive help in computation, and to Giorgio Krstulovic for fruitful discussions. We are grateful for to an anonymous referee for useful comments. The suggestions helped us improve the quality of the manuscript substantially. The computer simulations were performed on Shaheen II of the Supercomputing Laboratory at King Abdullah University of Science and Technology (KAUST) under the Project No. K1052. This work was supported by the Indo-French research project IFCPAR/CEFIPRA Contract No. 4904-A, and by the Indo-Russian project (DST-RSF) Project No. INT/RUS/RSF/P-03.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Condensed Matter Physics