Hi, This is a quite advance question. We need to get into it quite a bit. Let me see whether this will help. The strong magnetic field inside the sunspots usually do not directly extend to the Earth, because the strong fields are usually closed to themselves near the surface of the Sun. Only open magnetic field is far reaching and being carried by the solar wind to the Earth and beyond. When the open solar magnetic field reaches the Earth, it has expanded and usually quite weak ~5nT. Every now and then, however, stronger magnetic field can be seen in the solar wind at the so-called solar wind stream interaction regions and in Coronal Mass Ejections (CMEs). The Sun sends out fast and slow solar wind from different regions, and when fast wind catches up with slow wind, it will disturb the material and the compress the magnetic field. When there is a Coronal Mass Ejection (CME), it ca carry part of the strong magnetic field in a Sunspot to the Earth. These strong magnetic fields can be 10 times of the background magnetic field in the solar wind at quite times. Now the interaction between the strong magnetic field with the Earth's magnetosphere has more stories to tell. The solar wind magnetic field and Earth magnetic field can connect together. The solar wind energetic particles can travel along the field lines, enter the Earth's magnetosphere and Ionosphere, and causes the colorful aurora. Yan