The magnetic fields of planets and stars are thought arise from a sort of continuous electrical generator driven by the turbulent flow of an electrically conducting fluid. This "dynamo effect," proposed in 1919 by Larmor, is widely accepted as a likely explanation for the dynamic, strong, and long lasting magnetic fields of astrophysical objects. However, the wide range of time and length scales relevant to turbulent flows at realistic geophysical and astrophysical parameters prohibits direct numerical simulation, and makes any computational study difficult and time intensive. Laboratory experiments can provide a great deal of data in parameter space beyond that reached in practical theoretical studies and that occupied by planets and stars. Experiments remain a useful tool for developing an understanding of the rich variety of phenomena that arise in turbulent flows of magnetized fluids.


Our experiments

Dynamo 1Dynamo I
Our first rotating convection sodium experiment (20 cm diameter).

Dynamo 2Dynamo II
A mechanically driven sodium device (30 cm diameter).

Dynamo 3Dynamo III (60 cm)
Our second rotating convection sodium experiment (60 cm diameter).

Dynamo 3.5Dynamo 3.5 (60 cm)
A modification to Dynamo III to allow mechanical drive of an inner shaft (instead of convection) in addition to rotation of the outer vessel.

3 meter system3 meter system
Mechanically driven and rotating, like Dynamo 3.5 (3 m diameter).

Bigger is better when it comes to dynamo experiments. The larger the experiment, the larger the magnetic Reynolds number. The larger the magnetic Reynolds number, the better your chances are to self-generate magnetic fields.

Scales of the dynamo experiments.


These experiments use liquid sodium as the test fluid because of its high electrical conductivity. Sodium is chemically volatile, however, and using it safely requires caution, training, and specialized procedures. Oversight of our safety plan comes from two routes: the University of Maryland Environmental Health and Safety office, and the Engineering and Safety team at DuPont Sodium production facility. All of our safety plans and many refinements of those plans have been reviewed, and will be re-reviewed by these teams. Those recommendations will be strictly followed. Included in those plans are building modifications, personal protection equipment, and training. DuPont Corp. has given a day of training for both research personnel and the local fire department personnel on the safe handling and fire extinguishing practices for sodium. One pallet of drums of the soda ash fire fighting material will be on hand prior to receipt of the material. The safe conduct of our existing sodium experiments is some evidence of our ability to conduct these experiments, although the increased volume will require increased vigilance.