Electromechanical Dynamics (Part 1).0028

Electromechanical Dynamics (Part 1).0028 - where 1o is the...

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Electromagnetic Theory Symbols and Units of Electromagnetic Quantities Field Variable Name Magnetic field intensity Free current density Free surface current density Magnetic flux density Magnetization density Electric field intensity Electric displacement Free charge density Free surface charge density Polarization density Force density Permeability of free space Permittivity of free space MKS Rationalized Units A/im A/m 2 A/im Wb/m2 A/m V/m C/m 2 C/m 3 C/m 2 C/m2 N/m 3 47r x 10 - 7 H/m 8.854 x 10 - 1 2 F/m properties of the materials affect the field and source quantities. The magneti- zation density M is introduced to account for the effects of magnetizable materials. The most common constitutive law for M takes the form M = XmH, (1.1.6) where Z, is the magnetic susceptibility. An alternative way of expressing this relation is to define the permeability ~ = u,(l + X,,),
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Unformatted text preview: where 1o is the perme-ability of free space ou, = 47r x 10- 7 H/m, (1.1.7) in which case it follows from (1.1.4) that the constitutive law of (1.1.6) can also be written as B = uH. (1.1.8) We shall make considerable use of this simple linear model for magnetizable materials. Free currents in a stationary material most often arise from conduction induced by the electric field according to Ohm's law: Jf = oE, (1.1.9) where a is the conductivity (mhos/m). A similar constitutive law relates the surface current density K, to the electric field intensity E, tangential to the surface K, = rsEt, (1.1.10) where ar is the surface conductivity (mhos). These constitutive laws for the Table 1.1 Symbol H Jf K, B M E D Pf af P F Eo0 A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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