TOPICS
Search

Maxwell's Equations


Maxwell's equations are the system of partial differential equations describing classical electromagnetism and therefore of central importance in physics. In the so-called cgs system of units, Maxwell's equations are given by

del ·D=4pirho_f
(1)
del xE=-1/c(partialB)/(partialt)
(2)
del ·B=0
(3)
del xH=(4pi)/cJ_f+1/c(partialD)/(partialt),
(4)

where D is the electric displacement field, rho_f is the free charge density, E is the electric field, c is the speed of light, B is the magnetic field, H is the magnetizing field, and J_f is the free current density (cf. Purcell 1985, p. 330, 381, and 432; Jackson 1998, p. 818). As usual, del ·V is the divergence and del xV is the curl.

In the MKS system of units, the equations are written

del ·D=rho_f
(5)
del xE=-(partialB)/(partialt)
(6)
del ·B=0
(7)
del xH=J_f+(partialD)/(partialt)
(8)

supplemented by

D=epsilon_0E+P
(9)
H=1/(mu_0)B-M,
(10)

where epsilon_0 is the permittivity of free space, mu_0 is the permeability of free space, P is the electric polarization, and M is the magnetic polarization or "magnetization" (Griffiths 1998, pp. 278-279).


See also

Dirac Equation

Explore with Wolfram|Alpha

References

Griffiths, D. J. Introduction to Electrodynamics, 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, pp. 279 and 295, 1998.Jackson, J. D. Table 2 in Classical Electrodynamics, 3rd ed. New York: Wiley, p. 818, 1998.Purcell, E. M. Electricity and Magnetism, 2nd ed. New York: McGraw-Hill, 1985.

Referenced on Wolfram|Alpha

Maxwell's Equations

Cite this as:

Weisstein, Eric W. "Maxwell's Equations." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/MaxwellsEquations.html

Subject classifications