Editing Skin effect (section)

===Derivation===
Combining the [[electromagnetic wave equation]] and [[Ohm's law]] produces
<math display=block>
\nabla^2\mathbf{J}(r) + k^2\mathbf{J}(r) = \frac{\partial^2}{\partial r^2}\mathbf{J}(r) + \frac{1}{r}\frac{\partial}{\partial r}\mathbf{J}(r) + k^2\mathbf{J}(r) = 0.
</math>
The solution to this equation is, for finite current in the center of the conductor,
<math display=block>
\mathbf{J}(r) = \mathbf{C}J_0(kr),
</math>
where <math>J_0</math> is a [[Bessel function of the first kind]] of order <math>0</math> and <math>\mathbf{C}</math> is a constant phasor. To satisfy the boundary condition for the current density at the surface of the conductor, <math>\mathbf{J}(R),</math> <math>\mathbf{C}</math> must be <math>\frac{\mathbf{J}(R)}{J_0(kR)}.</math> Thus,
<math display=block>
\mathbf{J}(r) = \mathbf{J}(R)\frac{J_0(kr)}{J_0(kR)} .
</math>