What determines the spatial variation in phase in a superconductor?

I'm assuming that since a superconductor is in one common wave function, the time evolution is governed by the typical global phase variation:

$$\psi (t) = e^{-\frac{i}{\hbar}E_nt}\psi(0)$$

However, I cannot seem to find any good references that explain what makes it vary in space, in for example a long wire or an LC circuit. Can anyone point me in the right direction?

• Obviously Ginzburg-Landau theory. – Meng Cheng Jun 17 '15 at 2:49