一、结合粒子的运动轨迹来处理带电粒子在组合磁场中的周期性运动例1如图1所示,空间某平面内有一条折线是磁场的分界线,在折线的两侧分布着方向相反、与平面垂直的匀强磁场,磁感应强度大小都为B。折线的顶角∠A=90°,P、Q是折线上的两点,AP=AQ=L。现有一质量为m、电荷量为q的带负电微粒从P点沿 First, the particle trajectory to deal with the periodic motion of charged particles in the combined magnetic field Example 1 As shown in Figure 1, a plane in the plane of a broken line is the dividing line of the magnetic field, distributed in opposite directions on both sides of the polyline, Vertical uniform plane with a magnetic field, the size of the magnetic flux density B. The vertex of the polyline ∠A = 90 °, P, Q is the two points on the polyline, AP = AQ = L. There is a mass of m, the amount of charge q of negatively charged particles along the P point