Now, a team at the National Ignition Facility (NIF), which is a fusion experiment based at the U.S. Department of Energy’s Lawrence Livermore National Laboratory, has reported that the magnetic fields can boost the temperature of the fusion “hot spot” in experiments by 40 percent and more than triple its energy output, which is “approaching what is required for fusion ignition” according to a study published this month in Physical Review Letters.
“The magnetic field comes in and acts kind of like an insulator,” said John Moody, a senior scientist at the NIF who led the study, in a call with Motherboard. “You have what we call the hot spot. It’s millions of degrees, and around it is just room temperature. All that heat wants to flow out because heat always goes from the hot to the cold and the magnetic field prevents that from happening.” “When we go in and we put the magnetic field on this hotspot, and we insulate it, now that heat stays in there, and so we’re able to get the hot spot to a higher temperature,” he continued. “You get more [fusion] reactions as you go up in temperature, and that’s why we see this improvement in the reactivity.”
The hot spots in the NIF’s fusion experiments are created by shooting nearly 200 lasers at a tiny pellet of fuel made of heavier isotopes (or versions) of hydrogen, such as deuterium and tritium. These laser blasts generate X-rays that make the small capsule implode, producing the kinds of extreme pressures and temperatures that are necessary for the isotopes to fuse together and release their enormous stores of energy. NIF has already brought their experiments to the brink of ignition, which is the point at which fusion reactions become self-sustaining in plasmas. The energy yields created by these experiments are completely outweighed by the energy that it takes to make these self-sustaining reactions in the plasmas in the first place. Still, achieving ignition is an important step toward creating a possible “breakeven” system that produces more energy output than input. Moody and his colleagues developed their magnetized experiment at NIF by wrapping a coil around a version of the pellet made with specialized metals.
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