Large loops of magnetic current and confinement in four dimensional U(1) lattice gauge theory.

We calculate the heavy quark potential from the magnetic current due to monopoles in four dimensional U(1) lattice gauge theory. The magnetic current is found from link angle configurations generated in a cosine action simulation on a 24[sup 4] lattice. The magnetic current is resolved into large loops which wrap around the lattice and small loops which do not. It is shown that the long range part of the heavy quark potential, in particular the string tension, can be calculated solely from the large loops of magnetic current.