The motion of charged particles in a neutral magnetic field and the acceleration mechanism of auroral particles

This paper makes a systematic study on the motion of charged partciles in a neutral magnetic field by means of perturbation method, trajectory and the allowed region of particles. The motion can be divided into the drift motion, the “8” shape motion and the oscillation motion. In addition, there is a non-perturbation region in the neutral field. Interesting physical processes such as focussing, reflection, inverse motion as well as acceleration happen in this region. According to the acceleration with a dawn-dusk electric field we have suggested an acceleration mechanism of auroral particles which can explain why auroral particles are accelerated mainly along the narrow boundary of the polar cap.