Prof. Nuno Loureiro

Susan Young

Nuno Loureiro: In search of a more perfect fusion reactor

Francesca McCaffrey  |  MITEI Energy Futures

Nuno Loureiro is an assistant professor in nuclear science and engineering at MIT, is particularly attuned to the inner movement of complex systems. Much of his research on plasma theory and modeling concerns turbulence and magnetic reconnection, two phenomena that disrupt the operation of nuclear fusion reactors.

To Loureiro, MIT itself represents a fascinating system—one he’s been exploring since he joined the faculty in January 2016. “It’s great to be in an environment where the system will respond at the level you want,” he says. “Sometimes it’s hard to find an institution where there is a perfect resonance between what you want, the rhythm you want for your own research, and the institution itself. And MIT does this. MIT will basically respond to whatever you throw at it.”

What drew Loureiro to plasma physics, he says, was energy. “If one is not naïve about today’s world and today’s society, one has to understand that there is an energy problem. And if you’re a physicist, you have the tools to try and do something about it.”

Fusion reactors, with their potential to provide continuous, greenhouse gas emissions–free energy, are one answer to the problem. A working fusion reactor gleans its energy from the organized movement of plasma, a hot ionized gas, along tracks formed by magnetic bands within the reactor, similar to the way the solar plasma on the surface of the sun moves along paths dictated by the sun’s magnetic field. Loureiro, who specializes in plasma as it relates to both reactor physics and astrophysics, knows the details of this parallel well. Sometimes the magnetic field lines on the sun’s surface rearrange themselves, and the resulting “violent phenomenon” of energy release is a solar flare, Loureiro says.

Something similar can take place within fusion reactors. A reactor’s plasma occasionally will spontaneously reconfigure the prescribed magnetic field, inducing instabilities that may abruptly terminate the experiment. In addition, fusion reactor plasmas tend to be in a turbulent state. Both effects hinder the reactor’s ability to operate.

Loureiro uses theoretical calculations and supercomputer modeling to try to figure out what causes those phenomena and what can be done to avoid them in future experiments. He says, “When someone proposes a new concept for a fusion reactor, or when one is planning new experiments on existing machines, one of the things you have to think about is, how will the plasma in it behave?” His simulations use several theoretical approaches to tackle such questions. He notes that his simulations are not meant to be prescriptive, which would require a high level of complexity and realism. “My approach is at a more fundamental level,” he says. “I take very complex phenomena and try to understand them by reducing them to the simplest possible system that still captures the essential physics of those phenomena.”

Loureiro looks forward to continuing to involve more students in his research. In his lab and in the classroom, he already works with both undergraduate and graduate physics students. He is currently teaching a numerical methods class for graduate students in nuclear science and engineering, and an undergraduate introductory seminar on plasma physics and fusion energy. “One of the things that has impressed me most about MIT is how talented the students are,” Loureiro says. “People told me, ‘Oh, the students are just amazing.’ But I don’t think I expected just how amazing they are.”

He feels the same esteem for his fellow researchers. “It’s inspirational to be on the same campus as people in completely different areas from mine who are world leaders in their fields,” he says. “That’s something that is unique to MIT and that I find incredibly motivating.”

He’s also inspired by the vibrant environment of the Plasma Science and Fusion Center (PSFC). “I feel that some of the most interesting ideas in fusion right now are being explored at the PSFC,” he says. “It’s great to be an active part of that excitement.”

Topics: Plasma science, Plasma theory & simulation, Nuno Loureiro