Friction forces on charges moving outside of a conductor due to Ohm’s law heating inside of a conductor
Friction forces on charges moving outside of a conductor due to Ohm’s law heating inside of a conductor
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由于导体内部的欧姆定律加热，电荷在导体外部移动时产生摩擦力
DOI：
10.1119/1.18770
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发表时间：
1997
影响因子：
0.9
通讯作者：
A. Widom
中科院分区：
文献类型：
--
作者：
M. Tomassone;A. Widom
众所周知，电磁理论的本科生都知道，位于导体上方高度h处的电荷e感受到力Fstatic=−（e2/4 h2）N，其中N是导体表面的单位法向量。静电力是由于感应导体电荷密度。假设（i）带电粒子具有平行于导体表面的小速度V，以及（ii）感应导体电流服从欧姆定律，电导率为σ。欧姆定律在导体中感应加热，然后产生摩擦力（超过静力）Ffriction=−（e2/16πσh3）V。这种摩擦力的简单推导为本科生提供了一个有趣的物理例子，即感应摩擦力作用在一定距离处，即，在真空中移动的带电粒子可以感受到由于相邻导体而产生的摩擦力。
It is very well known and taught to undergraduate students of electromagnetic theory that a charge e sitting at a height h above a conductor feels a force Fstatic=−(e2/4h2)N, where N is a unit normal vector to the conductor surface. The static force is due to an induced conductor charge density. Suppose (i) that the charged particle has a small velocity V parallel to the conductor surface, and (ii) that the induced conductor currents obey Ohm’s law with conductivity σ. Ohm’s law induced heating in the conductor then gives rise to a friction force (over and above the static force) Ffriction=−(e2/16πσh3)V. A simple derivation of this friction provides the undergraduate student with an interesting physical example of an induced friction force acting at a distance, i.e., a charged particle moving in the vacuum can feel a friction force due to a neighboring conductor.