First plasma operation achieved in the new Pegasus Toroidal Experiment
Congratulations from researchers in England, Russia and the U.S. came almost immediately. In the world of spherical toruses, never had a research team achieved its first plasma so quickly. In early August, culminating almost two years of intense construction efforts, engineering physics Professor Raymond J. Fonck and his team of students reached a major milestone by generating a plasma on one of the first tries.
The Pegasus Plasma Experiment is a new fusion energy science research project in the Department of Engineering Physics. Researchers are studying high temperature plasmas (ionized gases) for applications to the development of fusion energy. Generating a plasma so quickly represents a major step in the development of this type of magnetic confinement device, says Fonck.
"For this particular type of device using magnetic induction to start the plasma, there is really only extensive experience with two in the world. The first one in England took six months to make a plasma and they had a really hard time doing it and so the folklore was out there that this was hard to do," says Fonck. "And then secondly there was a smaller one at Princeton, a little smaller than ours, that also struggled for about three months. The devices are very susceptible to small misalignments and mechanical problems. We had the students be very paranoid about that and it appears to have paid off."
To date, the most successful fusion plasma experiments have been based on the tokamak concept, which is a large toroidal (or donut-shaped) device with interlocking magnetic field coils designed to stabilize and confine the hot ionized gaseous fuel. While the largest such devices have produced up to 10 MW of fusion power, Fonck says conventional tokamaks suffer from very high projected costs, complexity and relatively low limits on the allowed plasma pressures, which in turn limits the economic attractiveness of the concept.
The goal of Pegasus is to explore theoretically predicted advantages of making the central hole in the "donut" as small as possible without losing the plasma to catastrophic instabilities. Fonck says this design allows the study of basic plasma physics concepts at high pressure, and in principle can lead to a much simpler and less expensive fusion device.
The Pegasus research team is somewhat unique in the fusion research community in its heavy reliance on student researchers who organize and execute all critical phases of the program. During the design and construction phase, the team consisted of Fonck, four academic staff scientists and technicians, three graduate students, and 20 undergraduate students from several academic departments. Student researchers covered responsibilities in all phases of design, analysis, and construction. Students will also perform experiments on the device, develop diagnostics and continue to further develop the facility. Fonck says national and international visitors from the plasma science research community have been impressed with the students' achievements.
"During the academic year, each student typically put in 10 or more hours per week in the laboratory, plus worked every Saturday (excepting home football games) and most holiday breaks," says Fonck. "Bringing the device from design to construction to operation on time and budget within the constraints of using a mainly student-based staff is an extraordinary achievement for the student team and the staff, and a testament to their hard work, talent and dedication."