Published online by Cambridge University Press: 01 January 1997
In this paper commemorating the 60th birthday of David Montgomery, issues tantalizing to me that evolved from my collaborations with him are highlighted: sustainment of the magnetohydrodynamic dynamo, relationships between discrete and continuous models of media, and closures for nonlinear theories of discrete and continuous media. In particular, it is speculated that a tractable statistical model of a magnetohydrodynamic dynamo may arise from a proper formulation of a solenoidal expansion basis for the magnetic and velocity fields in the context of an appropriate closure, such as the eddy-damped quasinormal Markovian model.