Staying the Course: Fusion Research

Pat Vail can still remember the feeling of awe that came over him when he first saw the Saturn V rocket and its massive F1 engines that sent men to the moon. His high school physics class was on a field trip to NASA’s Kennedy Space Center in Florida.


“That trip inspired my interest in America’s space program,” says Pat, ’17, a graduate student in Mechanical & Aerospace Engineering at Princeton. “I set a goal for myself during my senior year of high school to become an aerospace engineer so that I could one day be part of an undertaking as ambitious as the Apollo and Space Shuttle programs.”


Since then, Pat has not wavered from his mission to work on difficult engineering problems. As an undergraduate, he studied aerospace engineering and landed several prestigious internships, including a co-op at NASA that gave him the opportunity to work on rocket designs and observe astronaut training. Today, Pat works on a problem that has proven to be more difficult to achieve than sending men into space. As a graduate student at the Princeton Plasma Physics Laboratory, Pat’s research focuses on issues related to the development of nuclear fusion as a viable source of energy.


“The promise of fusion would be a complete game changer because it is a clean, carbonless energy source that produces minimal nuclear waste. The fusion fuel can be derived from abundant natural resources such as seawater. Fusion could therefore power our society for centuries,” explains Pat. “Today, we understand much of the science behind fusion, but the great challenge over the next 50 years or so is to advance the technology to the point that fusion can be produced in an economical way.”


Currently, the most promising type of experimental fusion facility is known as the tokamak—a donut-shaped device which confines plasma using powerful magnets. One of the greatest challenges in making fusion a viable energy source is that the plasma within the tokamak exists at an extremely high temperature—approximately 100 million degrees Celsius. As a result, the extreme heat flux from the plasma can damage the walls of the tokamak.


Pat is working to develop a novel magnetic field configuration called the “snowflake divertor” that can mitigate the heat exhausted from the confined plasma. Since the snowflake divertor’s magnetic field is highly unstable, he is developing a control system that can regulate the configuration in real time. His team plans to test the snowflake divertor on Princeton’s tokamak, NSTX-U, in the next few months.  Eventually, the snowflake divertor may help to cool the walls of next-generation tokamaks such as, ITER in France.


When Pat explains his research to family and friends, he jokingly says that his team at Princeton is trying to cool a sun with a snowflake. Growing up in the suburbs of Chicago, he recalls being the only member of his household who did not think math and science were the worst subjects ever.


“My favorite movie to watch as a teenager was Apollo 13,” he recalls. “I even thought about trying to become an astronaut for a while.”


Pat ultimately pursued engineering, but his work experience did bring him front and center with astronauts in the space program. Before coming to Princeton, Pat was part of a cooperative education program at NASA’s Johnson Space Center (JSC) in Houston. While working at the Neutral Buoyancy Laboratory, he gained SCUBA certification and observed spacewalk training in the world’s largest indoor pool, which contains a full-scale mockup of the International Space Station.


The co-op at NASA also gave him his first exposure to designing and building real engineering hardware. Pat helped design a prototype of a lunar lander for use in a proposed NASA project with the goal of landing a humanoid robot on the Moon in 1,000 days. Later, during an internship at a private company, Space Exploration Technologies (SpaceX), he developed a new manufacturing process that may lead to cheaper and more efficient rocket combustion chambers.


“These opportunities prepared me to be part of the entire development process in my current research project. We design a control system, write code for the device, and then implement and test the control on the real machine,” he explains.


For Pat, one of the most enjoyable aspects of engineering research is the opportunity for international collaboration. During an internship with a Chinese electronics company in Shanghai and as an engineering student at Peking University in Beijing, he had an opportunity to witness first-hand the global nature of the engineering profession.


“Being in China changed my entire world view,” says Pat. “I realized that developing international partnerships is essential when you are undertaking a huge engineering project. This is certainly true for fusion research.”


While fusion research has endless potential, it has also been a source of frustration for scientists for over half a century. When Pat hits a roadblock, he goes for a run to clear his head. Despite every setback, what drives him to succeed is realizing the societal benefits of fusion research.


“Scientific discoveries and new technologies that are generated by the fusion and space programs have larger benefits for humanity and can continue to improve life on Earth,” he said. “Being able to have that influence is what drove me to become an engineer in the first place.”


-Carolyn Sayre