带电粒子在圆形磁场区域过定点问题是近几年出现的物理情景新颖、构思独特的试题 .根据磁场的边界情况可分为两种类型 :一是圆形磁场区域边界为绝缘刚性圆筒 ,带电粒子与圆筒做弹性碰撞 ,周期性的在匀强磁场里做轨迹相同的匀速圆周运动而通过边界上某一特定点 ;二是与圆形磁场 The problem of over-fixed point of charged particles in a circular magnetic field is a novel and uniquely conceived test scenario in recent years. According to the boundary conditions of magnetic fields, it can be divided into two types: First, the boundary of a circular magnetic field is insulated rigid cylinder, The charged particles collide elastically with the cylinder and periodically perform a uniform circular motion with the same trajectory in a uniform magnetic field and pass through a certain point on the boundary; the second is a circular magnetic field.