Dynamos of the Sun and Stars, and Associated Convection Zone Dynamics

Peter A. Gilman
1983 Symposium - International astronomical union  
I see my assignment in this talk as being to focus on the interaction between the magnetic fields produced by dynamo action and the dynamics of the fluid flow which drives this dynamo, and to make some connections to the solar and stellar dynamo problems. To do this really requires we start with a fluid dynamical model that satisfies relevant laws of fluid dynamics, and in which the flow can actually respond to the induced magnetic field. Thus the so-called kinematic dynamo models are not
more » ... for our purposes, and we must address the full MHD dynamo problem in a self-consistent way. For example, we do not allow ourselves the license to vary independently the convection and differential rotation, as is commonly done in kinematic dynamo calculations, because the laws of physics do not allow that. We have been attempting to do self consistent MHD dynamo modeling at Boulder for the past several years, starting from a nonlinear fluid dynamical model for convection in a rotating spherical shell. This model we believe is physically complete in itself, with a minimum of ad hoc assumptions. It is much simpler than the real sun, but contains a lot of the physics we consider most relevant to the solar and stellar dynamo problem. I like to view the model more as an analog to the solar or a stellar convection zone, rather than as an approximation—much as a laboratory rat or monkey is used as an analog to a human being in many medical experiments. Each exists and is physically complete, and much, though not all, of their biochemistries are the same or are closely related.
doi:10.1017/s0074180900029910 fatcat:n7e6rg6ztne57ej44cbaqpx4me