Fig. 1

Components of the Earth’s magnetic field. a Orientation of the dipole field with respect to Earth’s rotation axis. b Measuring the field in the NEC coordinate system. B is the field vector, H its horizontal component, I the inclination and D the declination. c Earth’s magnetosphere is dynamically distorted by the solar wind carrying the Interplanetary Magnetic Field (IMF), which depresses the magnetosphere on the day side and extends its shape on the night side. Magnetosphere is the region of space around the Earth that is affected by its magnetic field. Bow shock marks its outermost boundary, where the speed of solar wind decreases. In magnetosheath, the Earth’s magnetic field is affected by the shocked solar wind and becomes weak and irregular. In magnetopause, the pressure from the Earth’s magnetic field and the solar wind are in balance - the size and the shape of magnetopause therefore constantly change in response to temporal variability in the speed, direction and strength of the solar wind. Magnetotail is the extended anti-sunward part of the magnetosphere: in reality the sphere is not a sphere (as in panel a) but has a large extended tail, created through the pressure of the solar wind