Electrodynamics MOC

Maxwell's equations in materials

By introducing the auxiliary โƒ—๐ƒ-field and โƒ—๐‡-field and separating free charge and current from those arising from electric polarization and magnetization, Maxwell's equations may become

  1. GauรŸ's law for diรซlectrics
  2. GauรŸ's law for magnetic flux
  3. Faraday's law of induction
  4. Ampรจre's law for magnets

Differential form

  1. โƒ—โˆ‡โ‹…โƒ—๐ƒ=๐œŒ๐‘“
  2. โƒ—โˆ‡โ‹…โƒ—๐=0
  3. โƒ—โˆ‡ร—โƒ—๐„=โˆ’๐œ•โƒ—๐๐œ•๐‘ก
  4. โƒ—โˆ‡ร—โƒ—๐‡=โƒ—๐‰๐‘“+๐œ•โƒ—๐ƒ๐œ•๐‘ก

Integral form

  1. โŠ‚โŠƒโˆฌ๐œ•ฮฉโƒ—๐ƒโ‹…๐‘‘โƒ—๐š=โˆญฮฉ๐œŒ๐‘“๐‘‘๐œโ€ฒ
  2. โŠ‚โŠƒโˆฌ๐œ•ฮฉโƒ—๐โ‹…๐‘‘โƒ—๐š=0
  3. E=โˆฎ๐œ•ฮฃโƒ—๐„โ‹…๐‘‘โƒ—โ„“=โˆ’๐œ•ฮฆ๐ต๐œ•๐‘ก=โˆ’๐œ•๐œ•๐‘กโˆฌฮฃโƒ—๐โ‹…๐‘‘โƒ—๐š
  4. โˆฎ๐œ•ฮฃโƒ—๐‡โ‹…๐‘‘โƒ—๐ซ=๐œ‡0(๐ผ๐‘“,ฮฃ+๐œ•ฮฆ๐ท,ฮฃ๐œ•๐‘ก)=(โˆฌฮฃโƒ—๐‰๐‘“โ‹…๐‘‘โƒ—๐š+๐‘‘๐‘‘๐‘กโˆฌฮฃโƒ—๐ƒโ‹…๐‘‘โƒ—๐š)

Sources

Noting the expressions for bound charge density and bound current density, as well as current due to changes in electric polarization density, we have

๐œŒ=๐œŒ๐‘“+๐œŒ๐‘=๐œŒ๐‘“โˆ’โƒ—โˆ‡โ‹…โƒ—๐โƒ—๐‰=โƒ—๐‰๐‘“+โƒ—๐‰๐‘+๐œ•โƒ—๐๐œ•๐‘ก=โƒ—๐‰๐‘“+โƒ—โˆ‡ร—โƒ—๐Œ+๐œ•โƒ—๐๐œ•๐‘ก


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