Three-dimensional exponential mixing and ideal kinematic dynamo with randomized ABC flows.

Abstract

In this work we consider the Lagrangian properties of a random version of the Arnold-Beltrami-Childress (ABC) flows in a three-dimensional periodic box. We prove that the associated flow map possesses a positive top Lyapunov exponent and its associated one-point, two-point and projective Markov chains are geometrically ergodic. For a passive scalar, it follows that such a velocity is a space-time smooth exponentially mixing field, uniformly in the diffusivity coefficient. For a passive vector, it provides an example of a universal ideal (i.e. non-diffusive) kinematic dynamo.