... The are two main sources of magnetospheric electric fields. The other is the solar wind related, dawn-to-dusk directed ("convection") field, and the other is the co-rotation electric field related to the rotation of the Earth along its spin axis. The electric fields have a strong effect on the drift paths of the magnetospheric plasma . ... The energetic particles, following the magnetic drifts more readily, are also affected by the convection field. ... Space Physics Text Book of Oulu ...