Centrifugally Confined Plasmas: An Alternative Approach to Fusion
The Sun and all other stars burn because of fusion. Physicists (at least two National Academy of Sciences studies) agree that it should be possible to use magnetic fields to make a star on Earth and use the fusion energy to build power plants on the GW scale. In the last 30 years, tremendous progress has been made: fusion energy output from tokamaks, the mainline approach to magnetic fusion, has risen by more than a 100-billion-fold. An $8B international tokamak fusion experiment, ITER, will be completed in the next 10 years and, all indications agree, will be the first self-sustaining net fusion energy producing burning star ever built on Earth. A demonstration power plant is expected to be the next step after ITER.
The potential advantages of fusion energy are many: practically zero-cost fuel, no possibility of meltdown, no easy proliferation, < 100 year low level waste, no carbon emissions. The questions that remain are cost-competitiveness (estimates at 15-20 cents/KWh) and the complexity and maintainability of the tokamak-based concept. Given, on the one hand, the sheer enormity of the task (making a star) and, on the other, very high pay-off for future world energy security, continuing research in the optimization of the tokamak and related concepts as well as innovations beyond the tokamak are undoubtedly called for.
At UM, we are experimenting on the feasibility of a highly novel approach to magnetic fusion. The tokamak is basically a loop of magnetic wire that is closed on itself with hot fusion fuel particles held together in star formation much as beads on this wire (left pic, below). Translated into physics reality, this makes for a system that can create a star but at the cost of large size and engineering complexity, in particular, large, inter-nested current coils. The UM approach uses centrifugal force: bend the magnetic wire into coat-hanger shape (right pic) and spin it supersonically; the beads will accumulate and be held in centrifugally at some maximum distention point on the wire. Translated, this yields an exceedingly simple current coil structure leading to less complexity and possibly smaller size. A proof-of-principle experiment, The Maryland Centrifugal Experiment (MCX), is on the way. It has achieved two of its three objectives. If all goes according to the physics projections, a next-level upgrade with stronger magnetic fields, a $2M/year class experiment, can be envisioned.