Using unmagnetized plasmas to produce dynamos

Constructing a laboratory example of a homogeneous dynamo is a long-standing problem with several examples of qualified successes. Studies using the Madison Dynamo Experiment have demonstrated the robust contribution of large-scale eddies to the mean field induction. By controlling the formation of eddies from unstable shear flow, we demonstrate that the concept of a turbulent resistivity is robust in low magnetic Prandtl number flows. Estimates based on rough mean-field theory $\beta$-effect calculations are in good agreement with experimental measurement. The limitations of liquid metal experiments lead to the desire for a different approach. A new platform for creating, driving, and diagnosing unmagnetized plasmas is being developed to facilitate a dynamo experiment that can explore broad parameter ranges of fluid viscosity and resistivity. Such a device provides both opportunities and challenges in incorporating physics beyond MHD such as ion-neutral drag and collisionless plasma phenomena.