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Fusion—Heating the core
Fusion—Heating the core
Scientists use a laser to align the plasma created at the Proto-MPEX machine at ORNL. Credit: Ted Biewer/Oak Ridge National Laboratory, U.S. Dept. of Energy

In a recent study, researchers at Oak Ridge National Laboratory performed experiments in a prototype fusion reactor materials testing facility to develop a method that uses microwaves to raise the plasma’s temperature closer to the extreme values reached in a fusion energy reactor’s exhaust system. The test platform, known as Proto-MPEX (precursor to the future MPEX facility), creates a linear-shaped plasma suitable for testing novel metal alloys, materials that could protect the plasma-facing walls inside fusion reactors from high temperature plasmas that reach millions of degrees. “To deliver the high temperature needed to simulate fusion plasma—which comprises electrons and ions—we demonstrated a scheme that heated core electrons to produce high heat flux plasma onto a material target,” ORNL’s Ted Biewer said. This method, combined with other methods, applied to Proto-MPEX helps raise the plasma’s temperature to achieve heat fluxes approaching 10 megawatts per square meter, similar to what is expected in ITER, the International Tokamak Experimental Reactor.—Sara Shoemaker