Electron spiralling is related to the earth’s magnetic field. Due to the convergence of the field lines, electrons are, in general, continuously accelerated towards the equatorial plane. The first object of the present investigation has been to determine how far along a particular field line (to the North or to the South) the spiralling electrons travel—that is, the distance to the ‘mirroring point’ at which their longitudinal velocity is reduced to zero and the reversed spiralling motion begins. This mirroring point is expressed in terms of the co-latitude 0, and is dependent on the ratio (u/v)0, that of longitudinal to transverse electron velocity at the equatorial plane.
See http://xumfak.my1.ru/Model_of_Tubes_of_Force_of_the_Earth.pdf for details.
To be continued...