高等电磁波理论 课件 第一章 电磁场基本理论.pptx

第一章电磁场基本理论

1.1麦克斯韦方程1

2AndreMarieAmpere(1775-1836)螺旋管的磁场IBB长导线的磁场安培定律（1826年）

3MichaelFaraday(1791-1867)BB磁场随时间变化VgenVgenB面积随时间变化VgenNSNS法拉第定律（1831年）

4Faraday’slawofinductionThelawofallseaandallland—Nolies,nodeceit,nocorruptionInthislawsocompleteandsogrand!Ourchildrenwillsingitinchorus–“CirculationofvectorcapE,”Yesthey’llsingastheymarchonbeforeus,“EqualsnegativedbydtOf–Magneticfluxthroughasurface,”?2001WalterFoxSmith法拉第定律之歌They’llconcludeaswestrikeuptheband.We’llmarkallourcoinswithourpurpose--“OnMaxwell’sequationswestand!”It’sFaraday’slawofinductionThatallowsustogeneratepow’r.Itgivesvoltageincreaseorreduction--Wecouldsingonandonforanhour!..矢量电场积分=穿过表面磁通量的时间微分赋予“力量”--电压增减

5Inside,outside,countthelinestotell–Ifthechargeisinside,therewillbenetfluxaswell.Ifthechargeisoutside,becarefulandyou’llseeThegoingsinandgoingsoutareequalperfectly.Ifyouwishtoknowthefieldprecise,Andthechargeissymmetric,youwillfindthislawisnice–Quponaconstant–eps’lonnaughttheysay–EqualsclosedsurfaceintegralofEdotndA.?2001WalterFoxSmith高斯定律（1832）闭合曲面的电通量积分=内部电荷总量×常系数《高斯定律之歌》“收支”平衡

6JamesClerkMaxwell(1831-1879)麦克斯韦-安培定律（1860）平板电容的失效E路径lII曲面S1曲面S2加个位移电流试试

7Mr.Ampere’smagical,mystical,wonderfullaw!OfMaxwell’sequations,itisthelongestandstrangestofall!Ontheleftside,hewrotecirculationOfmagneticfield,‘causeitwasneat.Ontherighthandsideofhisequation–Mu-naughtI–hethoughtitwascomplete.Decadeslater,Maxwellsawdisaster,AlthoughhethoughtofAmpereasasaint–InbetweentheplatesofacapacitorTherightside’szero,buttheleftsideain’t!安培定律之歌Tofixthisproblem,headdedtotherightsideDisplacementcurrent,abrandnewquantity!Itstartedmu-naughteps’lon-naughtandendedbyThetimederivativeofphi-sub-E.AndsotoMaxwellthemyst’rywasrevealed–Hesawhowlightcou