Generalized dilaton-Maxwell cosmic string and wall solutions
  The class of static solutions found by Gibbons and Wells for dilaton-electrodynamics in flat spacetime, which describe nontopological strings and walls that trap magnetic flux, is extended to a class of dynamical solutions supporting arbitrarily large, nondissipative traveling waves, using techniques previously applied to global and local topological defects. These solutions can then be used in conjunction with S-duality to obtain more general solitonic solutions for various axidilaton-Maxwell theories. As an example, a set of dynamical solutions is found for axion, dilaton, and Maxwell fields in low energy heterotic string theory using the SL(2,R) invariance of the equations of motion. 
John Morris