Effects of alpha-effect fluctuations on simple nonlinear dynamo models
| Autor: | Richardson, K. J., Proctor, M. R. E. |
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| Rok vydání: | 2010 |
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| Druh dokumentu: | Working Paper |
| DOI: | 10.1080/03091929.2010.521746 |
| Popis: | We investigate the interaction of a fluctuating alpha-effect with large-scale shear in a simple nonlinear 1-dimensional dynamo wave model. We firstly extend the calculations of Proctor (2007, MNRAS, 41, L39-L42) to include spatial variation of the fluctuations, and find that there can be a mechanism for magnetic field generation, even when the mean alpha is zero, provided the spatiotemporal spectrum of the fluctuations has an appropriate form. We investigate mean-field dynamo action when the new term arising from the fluctuations is non-zero, and present results concerning the stability and frequency of the solutions and parity selection in the nonlinear regime. The relation between the asymptotic theory and explicit simulation of a traditional mean-field model with a fluctuating function for the alpha-effect term is discussed. Comment: 18 pages, 10 figures, accepted in GAFD Special Issue - Natural Dynamos |
| Databáze: | arXiv |
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