Idea for a short story. Say you had a colony ship that had its atmo contained by acceleration alone. It had an atmo that was comparable in depth to a planet. (Don't worry about it escaping, just help me with the radiation aspect.) Think of Niven's Ringworld. How much radiation would you experience in interstellar space - say, a few light years from any stars? (discounting radiation from RW's sun.) While the RW's structure shields its denizens from radiation below, it doesn't help from above. Would you be able to shield the surface from radiation with a powerful magnetic field? Or an ozone layer? Would low relativistic velocities (.1%-1% c) blue-shift the radiation to any significant degree in terms of radiation exposure? Thx.