基于电磁学基本原理讨论了由两个相互平行的载流圆环构造的简单磁镜场的场分布以及均匀磁场中粒子运动的磁通量守恒量关系式.通过理论分析和数值模拟研究了在弱非均匀磁镜场中带电粒子的重力漂移运动，并运用重力漂移速度公式验证模拟结果，二者符合得较好，结果表明弱磁场下带电粒子所受重力会破坏带电粒子在磁镜场中运动的磁通量守恒关系.

Based on the basic principle of electromagnetism，we discuss the distribution of magnetic field of the mirror constructed by two parallel current carrying rings，as well the relationship of magnetic flux conservation for the moving particle in uniform magnetic field. The gravity drift motion of particle in weak inhomogeneous magnetic mirror field is studied by using theoretical analysis and numerical method. Our results consist with the formula of gravity drift in magnetic field，which show that the existence of gravity violates the conservation of magnetic flux in weak magnetic field.