I agree with GP, the measurable effects of the magnetic field are not strong, it's just that they're close because charged particles carried them close.
Maybe a better electromagnetic example would be radio signals from pulsars, which are enormous and travel great distances and still provide measurable signals even if they are light years away. We cannot on earth measure the gravity of these objects, nor the atomic forces, but we can readily meausure their electromagnetic sprayings.
Yet, nearly all of the extended structure of luminous interstellar gas we see in the best pics on APOD is the plasma fluid interaction that astrronomers can't be bothered about. SOFIA could have revealed much, if not grounded. Are any of the new orbital telescopes about to come online equipped to record polarization?
Maybe a better electromagnetic example would be radio signals from pulsars, which are enormous and travel great distances and still provide measurable signals even if they are light years away. We cannot on earth measure the gravity of these objects, nor the atomic forces, but we can readily meausure their electromagnetic sprayings.