Possibly. I've heard a lot about that kind of radiation shielding, and it would be really great because it eliminates the need for heavy physical shielding like water walls. From what I understand though, the main problems are generating a powerful enough field to envelope the crew module and protect it from solar flares and cosmic rays, and finding a low-mass, high-energy power source to power the thing. As for impact shielding though, that has to be physical, because you can't deflect micrometeorites and speedy dust particles with magnetic fields.
Not necesirily. New research shows that it is enough to install small source of magnetic field and it will do the job as long as field will interact with solar wind. Peculiar reactions that occur between magnetic field and solar wind should strenghten the shield and do the job of nuclear reactor worth of power. But this theory wasn't tested yet.