稳恒电流磁场与库仑电场的关系研究

用电磁学方法证明了电流元产生元磁场的3个方程的等价性;由稳恒电流元的磁场表达式导出了元磁场与载流电荷元产生的库仑电场的关系。讨论了该表达式的物理意义,指出,该表达式明确指出稳恒磁场是由电荷的定向运动产生的;稳恒磁场是以光速传播的,为否定＂超距作用＂的观点提供了新的依据。认为v×dE/c2表示了库仑电场力的无功功率,由此可知,稳恒电流的磁场可以由载流电荷库仑力的无功功率表示。这样的结果有利于初学电磁学的人正确理解磁场的产生、来源和传播。讨论了运用新的表达式求解磁场的方法,指出,运用电荷密度与载流子定向运动速度的乘积等于电流密度和点电荷的库仑场表达式的方法求解磁场甚为方便,如此做法可以省去传统的求解磁场必须掌握的复杂计算方法。并由此推断超导载流子的平均定向运动速度远远大于正常导体内载流子的定向运动速度,否则,超导电流不可能产生几十个特斯拉的磁场。

A Study of the Relationship between Steady Current Magnetic Field and Coulomb Field

This paper proves that three equations which are derived from current element producing magnetic field are equivalent by using methods of electromagnetic; the relationship between bit magnetic field and coulomb field generated by current-carrying electric charge from the magnetic field＇s expression of steady current element is derived. It discusses the physical significance of the expression, shows its definite illustration of steady magnetic field being generated by directional movement of electronic charge and spreading at the speed of light, therefore new basis for denying the perspective of Action at a Distance is provided. It is believed that v × clE/c^2 means the reactive power of Coulomb field, therefore, the magnetic field of steady current can be expressed by the reactive power of current-carrying charge＇s Coulomb force, which makes it easier for beginners to understand the generation, origin and spreading of magnetic field correctly. Besides, this paper discusses how to solve problems of magnetic field by our new expression. It proves that Charge density multiplying speed of current carrier＇s directional movement equals with current density multiplying point charge＇s coulomb field, this makes it simpler to solve magnetic field. This method can avoid complicated calculations which traditional way have to use. Furthermore, this paper clarifies that the average speed of current-carrier＇s directional movement in superconductor is much faster than in normal conductor; otherwise, current in superconductor will not be able to produce a magnetic field of dozens of Tesla.