My research focuses on understanding how electrical currents (and hence magnetic fields) are generated in fusion plasmas and in turbulent flows of liquid metals. I am an experimentalist, which means that I build devices and carry out experiments on these devices to answer fundamental questions like:

• Where do the magnetic fields found on planets and stars come from?

• How can magnetic fields be used to confine hot plasmas and create a burning star on Earth?

One of my experiments, the Madison Dynamo Experiment, uses a 300 gallon liquid sodium facility to study how magnetic fields are generated in turbulent flows of liquid metal (like the conditions found in the core of the Earth). The experiment uses two 100 Hp motors to drive flows in a spherical container that are expected to lead to self-generation of magnetic fields. My fusion research is carried out on the Madison Symmetric Torus where confinement and stability of a toroidal magnetic configuration known as the reversed field pinch is carried out. My research on MST focuses on studies of current transport, electron heat transport and microwave heating of electrons (to drive current) in the RFP geometry. I recently spent a year on sabbatical in Germany working on the ASDEX-U tokamak, studying similar questions on a large tokamak. I also direct research on a smaller, basic plasma physics experiment investigating the MHD stability of a line-tied screw pinch plasma. The experiment was constructed to test the hypothesis that two conducting shells, one rotating with respect to the first, can stabilize current driven kink modes in fusion plasmas. The experiment is also providing data about stability a geometry which is strikingly similar to the geometry of solar eruptions (solar flares or coronal mass ejections).

Some Recent Publications

• M. D. Nornberg, E. J. Spence, R. D. Kendrick, C. M. Jacobson, C. B. Forest, Intermittent magnetic field excitation by a turbulent flow of liquid sodium Phys. Rev. Lett. 97, 044503 (2006).
• R. A. Bayliss, M. D. Nornberg, P. W. Terry, and C. B. Forest, Numerical simulations of current generation and dynamo excitation in a mechanically-forced, turbulent flow, Phys. Rev. E. 75, 026303 (2007)
• M. D. Nornberg, E. J. Spence, R. D. Kendrick, C. B. Forest. Measurements of the Magnetic Field Induced by a Turbulent Flow of Liquid Metal. Phys. Plasmas 13, 055901 (2006).
• E. J. Spence, C. B. Forest, M. D. Nornberg, R. D. Kendrick, Observation of a Turbulence-Generated Large Scale Magnetic Field. Phys. Rev. Lett. 96, 055002 (2006).
• W. Bergerson, C. B. Forest, G. Fiksel, D. Hannum, R. Kendrick, J. Sarff, and S. Stambler, Onset and saturation of the kink instability in a current-carrying line-tied plasma, Phys. Rev. Lett. 96, 015004 (2006).
• J.K. Anderson, T.M. Biewer, C.B. Forest, R. O'Connell, S.C. Prager, and J.S. Sarff, Dynamo-free plasma in the Reversed Field Pinch, Phys. Plasmas 11, L9 (2004).

Acknowledgements

My work has been generously supported by

• Office of Fusion Energy Sciences in the US Department of Energy
• The National Science Foundation
• The David and Lucille Packard Foundation
• The Alfred P. Sloan Foundation
• The Alexander von Humboldt Foundation