Classical electromagnetism - Wikipedia, the free encyclopedia Page 1 of 6
Classical electromagnetism From Wikipedia, the free encyclopedia (Redirected from Classical electrodynamics)
Classical electromagnetism (or classical electrodynamics ) is a Electromagnetism branch of theoretical physics that studies consequences of the electromagnetic forces between electric charges and currents. It provides an excellent description of electromagnetic phenomena whenever the relevant length scales and field strengths are large enough that quantum mechanical effects are negligible (see quantum electrodynamics). Fundamental physical aspects of classical electrodynamics are presented e.g. by Feynman, Electricity · Magnetism Leighton and Sands, [1] Panofsky and Phillips, [2] and Jackson. [3] Electrostatics Electric charge · Coulomb's law · The theory of electromagnetism was developed over the course of the 19th century, most prominently by James Clerk Maxwell. For Electric field · Electric flux · a detailed historical account, consult Pauli, [4] Whittaker, [5] and Gauss's law · Electric potential · Pais. [6] See also History of optics, History of electromagnetism Electrostatic induction · and Maxwell's equations . Electric dipole moment · Polarization density Ribari and Šušterši [7] considered a dozen open questions in the current understanding of classical electrodynamics; to this end Magnetostatics they studied and cited about 240 references from 1903 to 1989. Ampère's law · Electric current · The outstanding problem with classical electrodynamics, as stated Magnetic field · Magnetization · [3] by Jackson, is that we are able to obtain and study relevant Magnetic flux · Biot–Savart law · solutions of its basic equations only in two limiting cases: »... one in which the sources of charges and currents are specified and the Magnetic dipole moment · resulting electromagnetic fields are calculated, and the other in Gauss's law for magnetism which external electromagnetic fields are specified and the Electrodynamics motion of charged particles or currents is calculated... Occasionally, ..., the two problems are combined. But the Lorentz force law · emf · treatment is a stepwise one -- first the motion of the charged Electromagnetic induction · particle in the external field is determined, neglecting the Faraday’s law · Lenz's law · emission of radiation; then the radiation is calculated from the Displacement current · trajectory as a given source distribution. It is evident that this · · manner of handling problems in electrodynamics can be of only Maxwell's equations EM field approximative validity.« As a consequence, we do not yet have Electromagnetic radiation · physical understanding of those electromechanical systems where Liénard–Wiechert potential · we cannot neglect the mutual interaction between electric charges Maxwell tensor · Eddy current and currents, and the electromagnetic field emitted by them. In spite of a century long effort, there is as yet no generally accepted Electrical Network classical equation of motion for charged particles, as well as no Electrical conduction · [8] pertinent experimental data, cf. Electrical resistance · Capacitance · Inductance · Impedance · Resonant cavities · Waveguides Contents Covariant formulation