An artificl magnetic feild has to do more than provide a sience bounuses. Its the Earths magnetic feild that makes life possible. So an artifical magnetic feild can also give a barrin planit, with presumibly no magnetic feild, additional food an happiness bounus, as well as a population growth bounus. ArtificIal magnetic feild canalso serve a a reqirment for terraforming barrin planets into fertile planets.