Internal structure of the Sun, cutaway illustration. At the Sun's core, hydrogen atoms undergo nuclear fusion, producing helium atoms and releasing heat and light energy as photons. These radiate outwards through the inner region (radiative zone) to the outer convection zone layer. Here, solar plasma rises in thermal columns to the visible surface (photosphere), creating convection cells (arrows) and granulation patterns on the surface. Intense magnetic fields on the surface of the Sun inhibit convection, causing regions of lower temperature (sunspots, dark spots). Solar prominences are shown erupting from the Sun's surface.