《Electromagnetism, principles and application》教学课件（PPT讲稿）Chapter 19 Maxwell,s Equations

Chapter 19 Maxwells Equations The Total Current Density J a The curl of b ■ Maxwells Equations Maxwell' s equations in integral Form

Chapter 19 Maxwell’s Equations ◼ The Total Current Density J ◼ The Curl of B ◼ Maxwell’s Equations ◼ Maxwell’s Equations in Integral Form

So far we have obtained maxwells four equations V·E=f+ V.B=0 OB V×E VXB=uo(Jf +Je);(steady G enerally

19. 1 The Total Current Density J There are three kinds of current densities as follows 1. The free current density J1 f The displacement current density OD a OP ot Eoe+ at 3. the equivalent current density in magnetic ma terial V×M

Thus the total current density is the sum a OP f + E0 E++V×M ot at =Jn+609t where J m is the volume current density in matter OP f Ot+V×M

19.2 The Curl of b The fourth Maxwell equation VXB-uoJf +Je);(steady) should be generalized with the currents Jf+Je re- placed by the total current Jt V×B=p40Jt OP 10(J+60aE++V×M) 0 (Jm+0。E) at or. rewritten as V×B-10∈0aE=p0Jm