2012/10/24 by Erico L. Rempel, Abraham C. -L. Chian, Abraham C.-L. Chian +3 · 31 citations
Biochemistry, Genetics and Molecular Biology · Engineering · Physics and Astronomy · #Chaotic #Chaotic mixing #Dynamo #Fluid dynamics and aerodynamics studies #Geomagnetism and Paleomagnetism Studies #Isotropy #Lyapunov exponent #Magnetic field #Magnetohydrodynamic drive #Magnetohydrodynamics #Nonlinear system #Saturation (graph theory) #Solar and Space Plasma Dynamics #astro-ph.SR #nlin.CD #physics.plasm-ph
paper · pdf · doi:10.1017/jfm.2013.290
published in Journal of Fluid Mechanics 729, 309-329 (Cambridge University Press)
arxiv created 2012/10/24 · openalex publication_date 2013/07/19 · arxiv updated 2013/11/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract Eulerian and Lagrangian tools are used to detect coherent structures in the velocity and magnetic fields of a mean-field dynamo, produced by direct numerical simulations of the three-dimensional compressible magnetohydrodynamic equations with an isotropic helical forcing and moderate Reynolds number. Two distinct stages of the dynamo are studied: the kinematic stage, where a seed magnetic field undergoes exponential growth; and the saturated regime. It is shown that the Lagrangian analysis detects structures with greater detail, in addition to providing information on the chaotic mixing properties of the flow and the magnetic fields. The traditional way of detecting Lagrangian coherent structures using finite-time Lyapunov exponents is compared with a recently developed method called function M . The latter is shown to produce clearer pictures which readily permit the identification of hyperbolic regions in the magnetic field, where chaotic transport/dispersion of magnetic field lines is highly enhanced.