Turbulent Dynamos on Bounded Domains and Their Generalization to the Geometric Transport Equation

Abstract

For any smooth bounded domain $\Omega \subset {\mathbb{R}}^3$, we construct a divergence-free velocity field $u\in L_t^1{W}^{1,p}(\Omega )$ for all $p<\infty$, and magnetic fields $B^{\epsilon }\in L_t^p{C}^m(\Omega )$ for all $p<\infty$ and $m\in \mathbb{N}$, that solve the kinematic dynamo equation and exhibit arbitrarily fast growth of any magnetic energy mode, uniformly in the vanishing-diffusivity limit $\epsilon \to 0$. The construction is based on the convex integration scheme of Modena-Székelyhidi and Cheskidov-Luo. The main novelty lies in the introduction of explicit potentials, which allow the solutions to be localized and avoid the need to work with the anti-curl operator. In addition, we present a unified scheme for the geometric transport equation (GTE), which encompasses both the transport and Maxwell equations.

49 pages, 4 figures