7.d=p→∮D.da=jp.dv→n[ba-b]=ou p=-p,→∮p.da=-∫P,dv→n[p-p]=-op e,目)=p。+p→∮8E.da-p。+po)dV→n[。-Ed]=u+p D.Polarization Current Density △Q=qNdV=qNd.da=p.da [Amount of Charge passing through surface area element da] di,-AQ-OP.da [Current passing through surface ot ot area element da] =Jp.da polarization current density -爱 Ampere's law: vx斤=j。+jn+8。t =3+OP +t+8。t =i+e.E+p可 -i+阳 6.641,Electromagnetic Fields,Forces,and Motion Lecture 7 Prof.Markus Zahn Page 4 of 276.641, Electromagnetic Fields, Forces, and Motion Lecture 7 Prof. Markus Zahn Page 4 of 27 ∇ ρ ⇒ ρ ⇒ − =σ ⎡ ⎤ ∫ ∫ ⎣ ⎦ ii i v a b u u su S V D = D da = dV n D D ∇ −ρ ⇒ − ρ ⇒ − = −σ ⎡ ⎤ ∫ ∫ ⎣ ⎦ ii i v a b P = P da = dV n P P PP sp ( ) ( ) a b o u P o u P o su sp S V ∇ =ρ +ρ ⇒ = ρ +ρ ⇒ − σ +σ E E da dV n E E = ⎡ ⎤ ⎣ ⎦ εε ε ∫ ∫ i ii v D. Polarization Current Density ∆= = = Q qN dV qN d da P da i i [Amount of Charge passing through surface area element da ] ∂∆ ∂ = = ∂ ∂ i p Q P di da t t [Current passing through surface area element da ] = J da p i polarization current density ∂ = ∂ p P J t Ampere’s law: u p o E xH J J t ∂ ∇ =++ ∂ ε ∂ ∂ =+ + ∂ ∂ u εo P E J t t ( ) ∂ =+ + ∂ u εo J EP t u D J t ∂ = + ∂ S V