Background and Local Magnetic Fields on the Solar Surface

Abstract

In the last chapter we described the strongest magnetic fields on the solar surface: those of sunspots. In fact, it is not only spots that possess magnetism. Magnetic lines of force pervade various parts of the solar disk and every layer of the solar atmosphere. Strictly speaking, there is no region which is a real vacuum for magnetism. Starting here, we shall devote three chapters to the solar magnetic fields outside spots. Roughly speaking, this chapter introduces the fields of different parts of the solar surface in the transverse direction and emphasis is laid on active features. Then, in the vertical direction, Chapter 6 will discuss the magnetic fields in various layers of the solar atmosphere with stress on quiet regions. The overall characteristics of the solar magnetism will be treated in Chapter 7. This kind of division is, of course, crude. Because various regions of the Sun may be interlocked and many phenomena closely connected, the contents of these chapters will inevitably have some overlaps and repetitions.

If the Sun had no magnetic field, it might be a quiet, “classical” star — if such stars exist, with no corona, chromosphere, sunspots, or solar activity. H. Zirin, Astrophysics of the Sun (1988).