Abstract
The Hamiltonian and wave functions are written as a function of the gauge-invariant magnetic field only. A variational calculation with an ansatz, separable in plaquette space, leads to Mathieu's equation for the wave functions and a self-consistency constraint. This we solve analytically in both the strong- and weak-coupling limit, and we calculate the string tension. We find the electric flux to be confined to a tube of finite radius for all couplings.