Slashdot Mirror
MIT Scientists Demo 150 Ton Magnet For Plasma Research
Dr.Luke writes "The dream of abundant fusion energy just got a step closer to reality. MIT scientists just demonstrated a mammoth 150 ton magnet that could be used to create powerful plasma container needed for a practical fusion power plant. The device produces a magnetic field 260,000 times stronger than that of Earth. Full story here."
In the article it says:
A superconducting magnet operated on a constant current, such as those used in Magnetic Resonance Imaging of the body, suffers no dissipation of electrical energy. That is not true, however, when a superconducting magnet is pulsed. And tests of the new magnet in pulsed operation showed that "initially [the electrical] losses were much higher than predicted," Minervini said.
With repeated operation, however, the magnet appeared to correct itself. "With each cycle the losses lessened until they reached a steady value a lot closer to what we'd predicted," Minervini said.
"We think we understand what's happening, at least qualitatively," he continued. "It has to do with interactions between the thousands of wires twisted into cables that in turn are coiled to form the magnet. We are essentially changing the electrical characteristics of the cable in a way that decreases losses over time."
No. That's restating the problem. You don't have the understanding bit here. What is going on that will change the (I presume) I squared R losses in the magnet.