Seminar on PDEs and Fluid Mechanics
Alpha unstable flows and the fast dynamo problem
Speaker: Massimo Sorella (Imperial College)Date: Wednesday, 26 March 2025 - 11:30Place: Aula Gris 1, ICMAT
Abstract:
The fast dynamo problem is a fundamental question in MHD concerning the ability of a flow to maintain magnetic fields without their growth being slowed down by resistive effects. In the passive vector equation, a simplified model, this can be formulated as the exponential growth in time of the L^2 norm of the solution under a Lipschitz flow, at a rate independent of resistivity. In this talk, I will present a construction of a Lipschitz, divergence-free, and time-independent velocity field that acts as a fast dynamo in the whole space for the passive vector equation thanks to the alpha effect. This is joint work with M. Coti Zelati and D. Villringer.
