只有磁场时，粒子运动的洛伦兹方程为 dp d而 m=- Pdzd时 =gevx B v dt dz P=(1+δ)R=(1+δ)q(Bp)。 (e)'= e 0 (e)'=0 (e)'=- -e +流+%]小币+夜+店 g+G-r-- xB= B 4040 1 1 1 1 1 2 z z x y z z x y z z z x z y z z z x x y y z dv x x v e x e y e v e x e y e dz x x x v e v x e v y e v e e x e x e y e y e x v                 =  + + + + + + +                                = + + + + + + + + + + +                                    = +   1 1 1 1 z z z z x z z y x x x v e v x v x e v y v y e                                + + + − + + + +                                 1 1 1 ( ) x y z x y z z z z z z z y z x z z z y z x x y z e e e x x x v B v x v y v v y B v B e v B v x B e v x B v y B e B B B                     = + = − + + + − + −                                   1 z z x y x v v e x e y e      =  + + +           P m v dP dv P dz dv qev B m qev B qev B dt dt v dt dz = =   =  ⎯⎯⎯→ =  ( ) 0 ( ) ( )0 P P qe B = + = +  1 1   