How does magnetic fusion work?

[Ben.meyer]

Magnetic fusion is controlling plasma while its undergoing fusion. Right? Well if plasma is neutral, how can the magnetic fields affect it?

 

[alemsalem]

currents running through wires are neutral but the magnetic field still affects them.
im not sure how it works, but i suspect that the positive and negative charges will spiral along the magnetic field lines with opposite senses (CW CCW)

 

[mfb]

im not sure how it works, but i suspect that the positive and negative charges will spiral along the magnetic field lines with opposite senses (CW CCW)

Right.
While the total plasma is uncharged, (nearly) all objects in the plasma are charged.

 

[Astronuc]

currents running through wires are neutral but the magnetic field still affects them.
im not sure how it works, but i suspect that the positive and negative charges will spiral along the magnetic field lines with opposite senses (CW CCW)

Correct, nuclei and electrons spiral along the magnetic field lines, and by that, the magnetic field lines are used to exert pressure on the plasma. The magnetic field is applied from the outside, and the strength falls off with distance into the plasma. Inside the plasma, it's the collisions that maintain containment. Neutral atoms (from recombination) may leak out of the plasma.

Magnets are also used to heat the plasma. A large central magnetic can be used to induced a current in the conductive plasma, just like a transformer core induces a current in a metal conductor. This current also induces a magnetic field that confines and compresses the plasma. Other fields help support the confinement and as well as provide some stability (which is very challenging).