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."

Comments

damN!

[Anonymous Coward]

Imagine a Beowolf cluster of these!!!111!!!

Re:I can see the quotes now...

[stienman]

Given that these are superconducting coils the amperage relates more to power than it does in a situation where the resistance is unknown.

In other words, amperage is simply a measure of the number of electrons passing a cross-section of the wire in a given period of time. In this instance it is enough to give significant measure of the input power.

It is, however, inadequate in measuring the output, but since they didn't give any further info in the article I chose not to expand my narrative further than the nebulous Amp.

Gravity: Not just a good idea, it's the law.

-Adam

Re:A pulsed 13 Tesla magnet and its problems

[caffeinated_bunsen]

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

Quick bit of advice: Don't casually presume that you know more about the subject of the article than the PhDs who contributed to it. The whole point of a superconducting magnet is that R=0, so there is no I^2 R loss* in the magnet.

But when you build a magnet like this, you can't calculate the magnetic force on every centimeter of superconducting wire in the whole thing. You also can't make the wire stay precisely where you put it. As the field builds up the first time, all the wires move around a little bit, due to the very large magnetic forces on them. This wastes some of the energy put into the field. As you cycle the field, the wires gradually move toward an equilibrium and the mechanical energy loss goes to zero.

I'm sure there are other factors, but this is the only one that I can remember off the top of my head. In fact, I know that there's more than this to the problem, because this is a well-known phenomenon that everybody who designs high-field magnets has dealt with. If it were as simple as this, they never would have mentioned it in the article.

* Of course, there are some losses in type II superconductors due to the motion of flux vorticies. But this doesn't behave quite like an Ohmic resistance, and the loss is really small in good alloys.