Graduate student Pablo Rodriguez Fernandez has students race magnets down sheets of various metals to demonstrate eddy currents.

Paul Rivenberg

Magnet races and neon sword

The PSFC helps San Jose discover plasma

Paul Rivenberg  |  PSFC

Plasma Science and Fusion Center (PSFC) scientists, graduate students and staff recently returned from the 58th annual meeting of the American Physical Society – Division of Plasma Physics, held this year in San Jose, CA. The meeting provided them with a venue for their seven invited talks, and numerous contributed talks and research posters, many dealing with the physics of fusion plasmas in tokamaks like MIT’s Alcator C-Mod, and using data from that machine’s final, record-breaking run. But the PSFC did not stop at discussing fusion with colleagues; they also welcomed the local community, students and teachers to experiment with hands-on activities geared to teach them some fundamentals of plasma physics.

The main event was the Plasma Sciences Expo on November 4 and 5, organized by PSFC communications and outreach coordinator Paul Rivenberg, This science festival included eighteen national and local research facilities, universities, science organizations and even high schools, all presenting hands-on opportunities to learn physics related to plasma science. Participants were encouraged to create fusion in a box at the Contemporary Physics Education booth, discover how lasers are used for fusion at the University of Rochester’s Laboratory for Laser Energetics (LLE), and experience the flow of electricity with Princeton Plasma Physics Laboratory’s Van de Graaff generator.

The PSFC filled one corner of the exhibition hall with popular demonstrations. Research scientist Phil Michael manned a device that allowed participants to test how effective their sunglasses or sunscreen is against the transmission of damaging ultraviolet radiation.

“I was occasionally surprised at how much some of the younger kids knew about ultraviolet radiation,” Michael observed, “but overall I think most people only had a vague understanding of sun protection issues. I think the demo helps to reinforce concepts most people should be aware of.”

Graduate students Libby Tolman (center back) and Norman Cao encourage students to gather around a plasma sword to learn about the fourth state of matter.

Graduate student Libby Tolman enjoyed her interactions with the public while overseeing the eddy current display, where participants are asked to “race” magnets down three different inclined surfaces, copper, aluminum and plastic.

Tolman explains, “The magnet slides fastest down the plastic, since plastic does not conduct. Currents induced in the metals by the changing magnetic field slow the magnets on the copper and aluminum slides. Before running the demonstration, I always asked the students which magnet they thought would win, and it was great to listen to their debates. They had many good ideas, and some came up with the correct answer even before I ran the demonstration.”

Graduate student Pablo Rodriguez Fernandez oversaw a number of demonstrations, including the “Plasma Sword.” The relatively simple demo excited participants as they completed a circuit on the handle with their thumb, making a glowing red plasma shoot up the length of a transparent sword.

Fernandez noted, “Kids come up with questions that you don’t think about when you learn the high-level stuff. For instance, some were asking how the plasma sword creates the plasma, and if there is an electric potential difference between the two ends of the sword. We believe the plasma is created in the lower part of the sword that you hold and then expands. But the question is tricky, because we didn’t build the sword!”

Most popular was a video game that demonstrates how magnets confine a burning plasma in a tokamak like MIT’s Alcator C-Mod. Groups of four to eight participants had to work cooperatively to keep plasma fuel spinning through a tokamak long enough to make fusion.

The Expo, and the PSFC’s participation, is sponsored in part by the U.S Department of Energy, Office of Fusion Energy Sciences. It is part of a larger APS-DPP effort to help educate students and the general public about plasma, its nature and its potential.

Topics: Plasma science