Plasma in a Magnetic Field

[Fischer777]

I was wondering, if plasma moves moves in the same direction as a magnetic field when placed in a magnetic field, it seems that plasma would be in a perpetual state of motion if suspended inside a torus created by ring magnets, such as a tokamak. Wouldn't this violate the laws of thermodynamics, because you would essentially be creating perpetual motion? Or am I missing something?

[Drakkith]

The magnets don't cause the plasma to move. The particles themselves are in motion due to thermal motion (heat). The magnetic fields merely confine and guide the plasma. If the plasma cools down too far the ions will combine with the electrons and the plasma will cease to be a plasma and turn back into a normal gas.

Particles will spiral around the magnetic field lines and will be repelled by a gradiant in the field, but other than that they magnets don't do much else.