Title: Secular and cycle variations of the IMF Bz component and some associated geophysical effects
Author: V.N.Obridko
Affil: IZMIRAN
Email: solter@izmiran.troitsk.ru
Authors: Shelting B.D., Levitin A. E., Golyshev S.
Affils: IZMIRAN
Abstract: It is generally believed that Bz component of the interplanetary magnetic field does not originate in the Sun, but is rather generated on the way from the Sun to the Earth. This opinion rests on the fact that the monthly and annual mean Bz values are very small. Besides, the conventional concept of the source surface field treats it as strictly radial. In the present work, we show that Bz values agree both in magnitude and in sign with the polar solar magnetic field and, thus, are determined by the global field of the Sun. A cycle of the global field lasts from one Wolf number maximum to another. It is shown that geophysical disturbances and, in particular, recurrent events, are much stronger in the cycles when the global solar field on the poles is positive. This result can be used for super-long-term prediction of geophysical activity.