[DiogenesLamp]

You can’t really because there is no Van Allen belt so all the atmosphere is venting into space blown off the planet by the solar winds. Mars must have cooled down and locked the iron core at the center from spinning in molten lava so it is not producing a magnetic field.

You have nailed one of the primary problems.

Could artificial magnetic stations at the poles be made strong enough to build a field large enough to do any good?

Yeah, the atmosphere continues to bleed off in chunks through an effect I believe they call "magnetic disconnect." It needs a magnetic field and it needs a lot more mass.

[Trumpinator]

Nuke the center of the planet? Melt the core to get it spinning again?