Tilgner, AndreasAndreasTilgner2020-12-102020-12-102017https://resolver.sub.uni-goettingen.de/purl?gro-2/75769Numerical simulations of the G.O. Roberts dynamo are presented. Dynamos both with and without a significant mean field are obtained. Exact bounds are derived for the total energy which conform with the Kolmogorov phenomenology of turbulence. Best fits to numerical data show the same functional dependences as the inequalities obtained from optimum theory.enjournal_article10.1103/PhysRevFluids.2.0246060003960677000032469-990X