Maxwell's "displacement Current" Concept Evolution History Research

From mid-eighteenth century to mid-nineteenth century,western scientists did a large number of electrical and magnetic experiments,and summed up a series of basic laws of electromagnetism which seemingly unrelated.Until the 1960 s,the Scottish physicist James Clerk Maxwell successfully established Maxwell's equations which has completeness,self-consistence and a highly mathematical symmetric form on the basis of the concept called displacement current so that he achieved a great integration of electricity,magnetism and optics.From the viewpoint of time dimension,this set of electromagnetic equations lays a solid theoretical foundation for the generation of special relativity and gauge theory in the future.Therefore,it has an important historical significance for us to correctly understand the development of the twentieth century physics by studying the concept called displacement current in Maxwell's equations.This paper uses the concept called displacement current in Maxwell's equations as a starting point.The purpose of this paper is to analyze and interpret the profound mathematical symmetry embodied in Maxwell's equations comprehensively by studying the specific content of the electromagnetic equations carefully,and associating with the academic background of electricity and magnetism at that time,and to explore the profound influence of Maxwell's equations on the content and research method of theoretical physics nowadays.This paper will focuses on the discussions about Maxwell's equations and displacement current in “The Scientific Papers of James Clerk Maxwell” mainly from three aspects:Firstly,it briefly introduced the life experience of James Clerk Maxwell and focused on the study of the electromagnetic equations.In addition,it dicussed the background of electrical and magnetic research before the mid-nineteenth century in detail,which provided a historical explanation for the generation of basic electromagnetic laws in Maxwell's equations.Secondly,it analyzed the formula content of Ampere's law in Maxwell's equations in detail,which makes a theoretical foundation for the analysis and research of the concept called displacement current.Then,starting from the papers on electromagnetism published by James Clerk Maxwell,we could explained the reason for the formation of the displacement current rationally by analyzing the mechanical model called molecular vortices in detail.Meanwhile,it streamlined the evolution and significance of this physical concept.Finally,it not only described the specific process from quantitative form of displacement current to Hertz's electromagnetic wave experiment,but also revealed the internal connection between the displacement current and the mathematical symmetric form of Maxwell's equations.Thirdly,taking the equations of electromagnetic field as a clue,and starting with the Lorentz covariance and local gauge invariance,it elaborated the main developments of modern physics after Maxwellian period,such as special relativity and general relativity,quantum electrodynamics,Yang-Mills gauge theory,Standard Model and so forth.We could concluded that the concept called displacement current had a profound influence on the content and research method of the twentieth century theoretical physics.