I don't understand what you are trying to propose. If you are using permanent magnets there will always be a N pole and a S pole entering a magnet structure, and this is an excellent target for any charged particle. The only way I know of to avoid this is to have an electromagnet in a loop . These would have to have power feeds, probably cooling feeds, etc. How would you spin them, especially in the radial directions I think you are suggesting? Having some angular momentum to the plasma cloud may or may not help. I've seen some suggestions that spinning the entire magrid might do this.
If you are talking about spinning permanent magnets, I'm guessing the spinwould have to be so fast that the pole of the magnent would have to rotate away faster than the ion or electron could approach it. For that to work the spin would presumably need to be near or above the speed of the particle. For an electron that would be some where in the neighborhood of 10 to 100 million meters per second. Depending on the size of the magnent, it would have to rotate at a rate well above 1 billion RPM. Impressive if you can do it!
Dan Tibbets