Minimalist large scale dynamo from shear-driven inhomogeneity
Autor: | Ebrahimi, F., Blackman, E. G. |
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Rok vydání: | 2019 |
Předmět: | |
Druh dokumentu: | Working Paper |
Popis: | We show that non-axisymmetric, non-helical perturbations in an unstratified shear flow produce a shear-plane averaged electromotive force (EMF) proportional to a spatially dependent kinetic helicity. This new "shear-driven $\alpha$-effect" can amplify shear-plane averaged magnetic fields, but is undiscoverable when invoking the homogeneity assumption for dynamo coefficients. It is a candidate mechanism underlying large scale field generation in astrophysical, laboratory, and simulated shear flows, and highlights the essentiality of correctly averaging dynamo coefficients and fields. Comment: 4 pages |
Databáze: | arXiv |
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