Coronal Weather Report







Modeling the Magnetic Sun to Forecast Space Weather

Like all stars, our Sun has many distinct layers. The deepest layer we can see optically is the photosphere and it is sometimes referred to as the solar surface. However, the Sun is completely gaseous and there is no solid surface like here on Earth. Above the photosphere the gas becomes more and more tenuous until the outermost atmosphere is reached, which is called the corona.

The Sun's magnetic field, now thought to be generated mainly in a thin zone about one third of the way down towards the center, penetrates all layers. Scientists are working to model the magnetic field from one layer to the next to help unravel the mysteries of how the magnetic field is generated, how it stores energy, and how it contributes to the dynamic activity we observe on the Sun.

Image Credit: Yohkoh

Dark sunspots in the photosphere of the Sun are evidence strong or concentrated of magnetic field there. You can see these dark spots in the image on the right. In the corona of the Sun magnetic fields reveal themselves through the hot gas which follows the twists and turns of the field itself. These magnetic field loops or arcades are visible in the lefthand image above, which was taken at the same time as the other. The illuminatd loops are often rooted in or near sunspots. These or neighboring structures sometimes erupt, as seen in an animated GIF movie (1763 k), causing episodes of disturbed "space weather"

Solar scientists involved in this research effort are using magnetic evidence available from observations of the photosphere as a base on which to build a model of magnetic field activity in the corona. Coronal activity directly impacts Earth's space weather, which affects our satellites and our communications networks, so a Coronal Weather Report for the Sun has practical applications. We hope the activities and tutorials presented here will help you develop a better understanding of the Sun's complicated magnetic field and how it affects life on Earth.