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Stretch, Twist, Fold: The Fast Dynamo
Introduction: the fast dynamo problem fast dynamo action in flows fast dynamo in maps. Methods and their applications: dynamos and non-dynamos magnetic structure in steady integrable flows upper
Lectures on solar and planetary dynamos
Introduction 1. Fundamentals of dynamo theory P. H. Roberts 2. Solar and stellar dynamics N. O. Weiss 3. Convection and magnetoconvection in a rapidly rotating sphere M. R. E. Proctor 4. Solar
Geometric generalised Lagrangian-mean theories
Many fluctuation-driven phenomena in fluids can be analysed effectively using the generalised Lagrangian-mean (GLM) theory of Andrews & McIntyre (J. Fluid Mech., vol. 89, 1978, pp. 609–646) This
Helicity is unnecessary for alpha effect dynamos, but it helps
Abstract We present a two-scale analysis showing that helicity is not required for an alpha effect and associated dynamo instability, and that lack of parity-invariance in the velocity field is
A geometric look at momentum flux and stress in fluid mechanics
We develop a geometric formulation of fluid dynamics, valid on arbitrary Riemannian manifolds, that regards the momentum-flux and stress tensors as 1-form valued 2-forms, and their divergence as a
Advected fields in maps—III. Passive scalar decay in baker's maps
The decay of passive scalars is studied in baker's maps with uneven stretching, in the limit of weak diffusion. The map is alternated with diffusion, and three different boundary conditions are