Geomagnetic field secular variations caused by magnetospheric processes

Geomagnetic field secular variations (SV), the sources of which are assumed to exist outside the Earth, are studied. Particular attention is given to the discussion of the properties and sources of quasi-two-year and 10-year variations. The analysis performed gives every reason to plot the following picture of studied SV from the sources outside the Earth. SV with T=10-11 years of solar origin remain nowadays the most studied type of secular variations from the external sources. Their space-time structure is investigated and a more developed physical model is designed. The quasi-two-year variations (in the form of a sum of global and local parts) are singled out in many observatories throughout the world. In different components from many observatories the local part may considerably exceed the global one, i. e. the ''signal/noise'' relation may be less than unity