When the National Spherical Torus Experiment-Upgrade (NSTX-U) project team performed tests on its magnets and electrical systems in February 2025 to prepare for operations, engineers, physicists and technicians gathered in the NSTX-U control room to view video and data from the experiment in real time on a large screen in a scene reminiscent of a NASA control room.
The information displayed at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) was collected by a complex network of software and computer systems created, maintained and operated by the Instrumentation and Control (I&C) group. The head of the group, Lisa Dixon, was among the I&C staff who gathered in the control room.
"It's exciting to see it all working together and that we're powering the machine - that these systems are working together," Dixon said.
The I&C group has grown from 21 to 29 engineers and technicians since Dixon started at PPPL in June 2024. The group, which is part of the Engineering Department's Experimental Operations Division, has focused on upgrading equipment and software and testing systems to prepare for the NSTX-U research operations in 2026.
The team has also continued to support similar systems for two other experiments at PPPL: the Facility for Laboratory Reconnection Experiments, which will study magnetic reconnection, and the Lithium Tokamak Experiment-β, a tokamak that studies how liquid metals could be used to improve plasma performance in fusion experiments. The team uses a plasma control system similar to that used at the DIII-D National Fusion Facility at General Atomics.
"We're very much a mission-driven place. I see that in how people work. Everyone has bought into what we have to do. We know the goals. To see that sort of talent and dedication around a technical field is very inspiring." - Lisa Dixon
Dixon compares the role of the software and computer systems her group manages to the "nervous system" of NSTX-U. The upgraded system collects and displays data from the magnets, electrical systems, water systems and diagnostics. That information, along with video and audio of the experiment, is displayed on the control room screen. Dixon's group is also responsible for the plasma control system that monitors magnetic fields during experiments, which is currently being upgraded. The magnetic fields help shape and contain the plasma in fusion experiments. At the same time, another system monitors the voltage and currents of the electrical system and the magnets through a real-time protection and control system that shuts down the experiment immediately if there is a risk of damaging the machine from excessive current or movement.
Dixon in the NSTX-U control room. (Photo credit: Michael Livingston / PPPL Communications Department)
The I&C group "helps to tie together those different major systems and ensures a smooth operation," Dixon explained. "All of those systems need to be operating and healthy in their own right, and a lot of what we do is to help connect those systems." The group also designs the computer systems that connect to more than 30 diagnostics on the machines.
An education in physics, a career in engineering
Dixon brings a unique set of skills to her position. She earned an undergraduate degree in physics from St. John's University in New York and master's and doctoral degrees in physics from New York University.
At the start of her career, Dixon was a research scientist at Pixie Scientific, a research and development medical equipment company based in New York. She went on to become head of manufacturing at the company.
Dixon then worked for more than nine years at ASML, an international semiconductor manufacturing company with more than 44,000 employees. She started as an engineer at the company in Wilton, Connecticut, and was promoted to several leadership project management positions. Her most recent role was leader of a group developing software and electronics for an optical alignment sensor.
Dixon grew up in Queens, New York, and lived in Connecticut with her family for about a decade. She and her husband, Tom, their 13-year-old son, T.J., and two large mixed-breed dogs, Beldin and Durnik, moved to a house more than 150 years old in Robbinsville Township, New Jersey, when Dixon took the job at PPPL. A long-distance runner and CrossFit enthusiast, Dixon wakes up at dawn most days to run and logs 30 to 40 miles a week.
Dixon said she liked the idea of having a more research-oriented job in which she could not only manage a team but also get her "hands dirty" doing hands-on coding or swapping out components in a computer rack. "There's a slightly different focus at a national laboratory that I thought would be hopeful for my own career development," Dixon said.
Building systems
Dixon said she has always been a curious person and became interested in engineering when she was still a student. She was drawn to the idea of building the systems that support research. "I like the idea of building something that will have a continuing life that people can build on over time. The notion of building a thing, maintaining it, adding to it and enhancing it attracted me to the engineering side of research."
Dixon in the Fusion Computing Center, which houses many of the computer systems used for NSTX-U. (Photo credit: Michael Livingston / PPPL Communications Department)
She took the job heading the I&C group because it allows her to lead a "really talented group of engineers and technicians" doing hands-on engineering on various tasks, Dixon said. "I was interested in a role where I could have that combination of the technical and different aspects of design and operations," she said.
She is also interested in supporting the mission of the Laboratory to develop fusion as a potentially limitless form of energy. "We know fusion works. We know it's happening every day in the sun," she said. "To leverage fusion as an energy source would be game-changing for humanity."
A liaison and an organizer
Dixon sees herself as both a liaison and an organizer. She coordinates work with researchers and engineers throughout the Laboratory, trying to bring enthusiasm and an ability to see the big picture.
Another part of her role is to ensure that her staff are working safely, she added. "I feel very responsible for the group," she said. "I feel I need to be a good example and set good expectations because we all have families; we all have people we go home to at the end of the work day."
A major goal for Dixon is making people in her group "feel safe and supported because if people have the ability to speak up and have the ability to perform their job safely and feel the support of the organization, we're all going to be successful."
Dixon said she has come to admire the talent and dedication in her group and the larger PPPL organization. "We're very much a mission-driven place. I see that in how people work. Everyone has bought into what we have to do. We know the goals. To see that sort of talent and dedication around a technical field is very inspiring."
