Solar activity causes changes in the magnetic field on the surface of the Earth. If these changes are insignificant, they do not affect life on Earth. However, rapid variations of the geomagnetic field, the so-called magnetic storms, which have the character of shock waves, may adversely affect living organisms (including humans), and the technical systems that people use. The book presents a conceptual design that allows prediction of electrical power system emergency conditions caused by magnetic storms. Finally, the authors' present a comprehensive analysis of perturbations in the low- and mid-latitude ionosphere during moderate recurrent geomagnetic storms.