注记一:在弛豫过程中,导电媒质内自由电荷体密度ρ随时间的变化规律与电荷守恒定律是相一致的。我们知道,无论是在宏观的还是微观的电动力学理论中,电荷守恒是一最基本的物理事实。即有连续性方程式对任意体积V求积分,可得方程(2)和(3)分别是电荷守恒定律的微分与积分形式,它们分别从不同的角度描述了 Note 1: In the relaxation process, the conductive medium free charge density ρ with time and the Law of conservation of charge is consistent. We know that the conservation of charge is the most basic physical fact, either in macro or micro electrodynamics. That is to say, there is a continuity equation to integrate any volume V. The equations (2) and (3) are respectively the differential and integral forms of the law of conservation of charge. They are described from different angles