Characterization of experimental dynamos

Laboratory models of geophysical magnetic field production require new expe ri-mental characterization methods. Self-generating liquid metal magnetic d ynamos are explored using two new experiments. Kinematic dynamo studies lea d us to charac-terize the magnetic field dynamics in terms of eigenvalues a nd eigenfrequencies of the induction equation. Observing the decay of magne tic field pulses indicates the real part of the leading eigenvalue of the i nduction equation, while a chirp magnetic field diagnoses the imaginary par t of the eigenvalue. Finally, a single-frequency applied magnetic field cha racterizes the structure of the velocity field. These measurements provide a new means to characterize and measure the approach to self-generation. We present data from numerical simulations and laboratory experiments using t hese techniques.