The Structure of Flux-tubes in SU(2)
  The spatial distribution of the action and energy in the colour fields of flux-tubes is studied in lattice SU(2) field theory for static quarks at separations up to 1 fm. Special attention is paid to the structure of the colour fields associated with an excited flux-tube with E_u symmetry. We compare our results with hadronic string and flux-tube models. Sum rules are used to extract generalised beta-functions, to describe the expected colour field behaviour and to cross check the methods used. 
A.M. Green, C. Michael and P.S. Spencer