I outlined three potential solutions to that problem earlier in the thread. So with the two you refer to, that makes 5 potential solutions just from people in this thread. The 3rd potential solution was a protective shell around Mars, which is more complicated but theoretically possible. A far simpler, smaller and easier version of a Dyson sphere, essentially, but still impossible with current technology. The other two solutions I referred to could be done with current technology. Not at all easily, but they could be done. It's not an insurmountable problem. The artificial magnetic field would have the advantage of not blocking the useful energy from the sun, so that would be a better solution than shielding. The lower level of useful energy from the sun is already a serious problem for humans on Mars, so lowering it still further is less than ideal. Any form of artificial protection would have problems. Life on Mars would be dependent on it working. No failure. No downtime. You'd need multiple redundancy and an extremely expensive level of reliability. But it's not impossible. Impractical? Too expensive? Quite possibly. But not impossible. It might also be dangerous. If a Mars colony ever became wholly self-sufficient, it might rebel. Colonies often do. It wouldn't be particularly difficult to devastate Earth from Mars. You don't need advanced technology. No sci-fi Death Star stuff. Just throwing rocks, basically. Not particularly difficult from the lower gravity of a Mars colony that would have to have some form of space travel. Just push some mass in the general direction of Earth. Earth's gravity well would do the rest.