The field of magnetic fusion research has mysteries to spare. How to confine turbulent plasma fuel in a donut-shaped vacuum chamber, making it hot and dense enough for fusion to take place, has generated questions — and answers — for decades.
As a graduate student under the direction of Department of Nuclear Science and Engineering Professor Anne White, Pablo Rodriguez-Fernandez PhD ’19 became intrigued by a fusion research mystery that had remained unsolved for 20 years. His novel observations and subsequent modeling helped provide the answer, earning him the Del Favero Prize.
The focus of his thesis is plasma turbulence, and how heat is transported from the hot core to the edge of the plasma in a tokamak. Experiments over 20 years have shown that, in certain circumstances, cooling the edge of the plasma results in the core becoming hotter.
“When you cool the edge of the plasma by injecting impurities, what every standard theory and intuition would tell you is that a cold pulse propagates in, so that eventually the core temperature will drop as well. But what we observed is that, in certain conditions when we drop the temperature of the edge, the core got hotter. It’s sort of heating by cooling.”
The counterintuitive observation was not supported by any existing theory for plasma behavior.
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