Dave Galloway School of Mathematics & Statistics, University of Sydney Strong-field nonlinear dynamos Wednesday 4th, May 14:05-14:55pm, Carslaw Building Room 373. In recent years nonlinear dynamo theory has been preoccupied with the issue of whether sufficiently strong magnetic fields can be generated to agree with what is actually observed in astrophysical objects. In particular, can the total magnetic energy (ME) produced by a dynamo be comparable with the total kinetic energy (KE) of the motions responsible for generating the fields? I will give some numerical examples where this is indeed the case, and exhibit scaling arguments which show that solutions are possible where the ratio of ME to KE is arbitrarily high, even for very low values of the diffusivities. Remarkably, some of these solutions are numerically observed to be steady and attracting, although at present we have only non-rigorous arguments that they are in fact stable. (This is joint work with Robert Cameron.)