The Sun as a stable star is in "equilibrium", with gravity pulling down on the gases that make up the Sun, and radiation pushing outward; gravity and radiation pressure are equally balanced. Magnetic effeccts are an additional concern. In the photosphere (the "surface) of the Sun, the magnetic field of sunspots prevents some heat from rising, and so the sunspots are cooler than the surrounding unspotted Sun. So yes, the magnetic field does keep some heat from rising, but that is an effect localized to the area at the surface and underneath the sunspot. There are always little events going on higher in the atmosphere that are caused by the magnetic field "snapping" like a rubber band, which releases energy, but there is not enough energy from those events to heat the corona to the temperatures we observe. Coronal heating is likely a combination of several types of events, we just haven't found the right combination yet. Parker Solar Probe will definitely help with this.
|