Let me take you to the less fashionable side of campus, away from the bustle of Kendall and the glitz of the Stata Center. Not far from Simmons Hall and the Z Center, on the other side of the tracks, you’ll find a cluster of shabby red-brick buildings not designed by I. M. Pei or Frank Gehry. Instead, the decidedly unposh series of converted Nabisco warehouses looks like a halfway house for Keebler elves. The road outside these buildings floods every time it rains. The offices aren’t pretty or ergonomic; the ones with windows are dark, and the ones without are downright scary.
This is the home of MIT’s Plasma Science and Fusion Center (PSFC), where we study plasmas, those superheated gases that make up the sun and fill fluorescent lights. We are a mélange of nuclear engineers, electrical engineers, and physicists, and just as the tracks separate us from the rest of campus, our interest in plasma separates us from the mainstream of our disciplines. A little too abstract to be engineers and a little too applied to be scientists, we sometimes call ourselves fusioneers, or electric milkmen. (The literal translation of the Chinese word for plasma is “electric milk.”)
I don’t go to MIT’s main buildings very often, because our labs are all on Albany Street, and most of the plasma classes are taught in our own little corner of campus. This isolation gives me peculiar views of the Institute; from here most of the buildings are hidden. The Green Building is visible, framed by the steam from the physical plant and the chimney of the test reactor. In my most distinct memories I can see it looming in the early-morning sun above the Great Dome like a smokestack above the boiler of a giant steam engine. From this side of the tracks, the school seems different, more industrial – like an engine, powerful and thirsty for fuel.
Why am I here, studying plasmas? Simply put, I’m here because so many of the world’s problems are tied to our means of energy production. I’m here because I dream of seeing the world run on a clean, almost limitless form of power, a contained burning plasma more than 10,000 times hotter than the surface of the sun.
I should also confess that I’m here because I think the PSFC has the coolest toys on the playground. For instance, the Alcator project uses a tokamak, a doughnut-shaped type of magnetic confinement device that will probably form the basis of future fusion reactors. Alcator’s tokamak lives in a concrete cell the size of a basketball court and holds a 30-million-kelvin plasma in a magnetic field 160,000 times as strong as the earth’s. The inner walls of the containment vessel are armored with molybdenum tiles to cope with the plasma’s heat, and its exterior is decorated with a dizzying array of sophisticated diagnostic tools designed to probe the most intimate properties of a substance so hot that no solid could hope to withstand contact with it. (We need to keep tabs on such things as temperature, density, and flows to help figure out why energy leaks out of the plasma faster than physical theory suggests it should – and how we can stop the leakage.) To keep the plasma stable, a current of up to two million amps is inductively driven through it; more than six megawatts of radio frequency power can be dumped into the plasma to heat it. All told, when Alcator runs, it consumes about as much power as the entire city of Cambridge. No souped-up Camaro could hope to compete with that! And Alcator is one of the least-exotic experiments running at the PSFC.
I still remember my open-house weekend, visiting Alcator’s control room, listening to the power supplies groan under their load, and watching on the monitors as the plasma formed in front of my eyes. I was inspired. I knew there was no place else I wanted to be.