Hi Zach,

no-one is really sure. It might be that the magnetic field that pops up through the solar surface to make a sunspot goes all the way down to the bottom of the solar convection zone, about 140,000km below the surface of the sun. Or it might be that it only goes down a few tens of thousands of km. Solar Physicists are working on ways to 'look inside' the sun, using the waves from 'sunquakes' (like scientists can find out what is inside the Earth by using Earthquakes) and maybe in a few years we will have an answer to your question.