H alpha magnetic synoptic charts of the Sun are processed for 1915-1999 and
the spherical harmonics are calculated. It is shown that the polarity dist
ribution of the magnetic field on H alpha charts is similar to the polarity
distribution of the Stanford magnetic field observations during 1975-1999.
The index of activity of the large-scale magnetic field A(t), representing
the sum of the intensities of dipole and octupole components, is introduce
d. It is shown that the cycle of the large-scale magnetic field of the Sun
precedes on the average by 5.5 years the sunspot activity cycle, W(t). This
means that the weak large-scale magnetic fields of the Sun do not result f
rom decay and diffusion of strong fields from active regions as it is suppo
sed in all modern theories of the salar cycle. On the basis of the new data
the intensity of the current solar cycle 23 is predicted and some aspects
of the theory of the solar cycle are discussed.