a 100 Tesla magnet is needed to test the properties of new high-temperature superconductors like iron oxyarsenide, which may improve the performance of MRI machines and high-voltage power lines while lowering their cost. A 100‑T magnet would also let you conduct certain zero-gravity experiments without traveling into space and let you develop magnetic propulsion systems that could eventually replace those that burn rocket fuel.
The Magnet Lab is close to reaching the material tensile strength needed to repeatedly break the 100-T barrier. It will have to resist enormous Lorentz forces—the electromagnetic push on electrons that attempts to force them in a direction perpendicular to the flow of current. In a 100-T magnet hese forces are “equivalent to the explosive force of 200 sticks of dynamite packed into a volume of space the size of a marble.”
The electromagnet will be made of two pieces—a thick, hollow cylinder, called an outsert, that’s 1.5 meters in diameter by 1.5 meters tall, and an insert just big enough to fit inside the outsert’s 225‑millimeter bore. The outsert will be powered by a 1.4‑gigawatt generator and produce fields between 40 T and 44 T, while the insert will draw enough current from a 2-megajoule capacitor bank to generate fields up to 60 T. The outsert is never powered up for more than 2 seconds at a time, during which the insert can deliver multiple 20‑millisecond bursts. Enough energy is transferred during those 2 seconds to raise the magnet’s temperature from the cryogenic cold of liquid nitrogen to nearly 200 °C. It takes an hour to cool the magnet enough to start another round of pulses. Boebinger says the design and composition will allow researchers to get roughly 10 000 pulses out of the $8 million outsert magnet and about 100 pulses before a $20 000 insert magnet is destroyed.
If you can imagine, it’s as if we were looking at passengers scrambling through Grand Central Station in New York, watching them run in different directions. All of a sudden, the whistle blows and we see them run to the same train. This is a simple example of a sudden transition to collective behavior,” Ong said.