Classical circular strings with pure SU(2) charge

Using Kaluza-Klein-like dimensional reduction techniques we obtain a classical string with a pure SU(2) charge. The string is embedded in the product of Minkowski space and the squashed 3-sphere, which has SU(2) as its isometry group. For certain values of the constants of motion the string can wind around the sphere without contracting to a point, in contrast to what is expected from the topology. This construction finally leads to a non-collapsing circular string in Minkowski space.