The sunspots are the most visible manifestations of the solar magnetic field. These are the places where the field lines emerge from the interior of the sun and form expanding loops above the solar surface. Good images of these loops can be found in the the Sacramento Peak Observatory exhibit on the sun. Temperatures in sunspot regions are considerably lower than the photospheric temperature because the strong magnetic fields supress energy transfer in these regions.
Active regions are composed of sunspots, faculae, plages, intense
magnetic fields and coronal condensations. They are the sites of
enhanced radio radiation, XUV sources and flares.