ON SIGMA MODEL FORMULATION OF GREEN-SCHWARZ SUPERSTRING

The Green-Schwarz covariant superstring action is consistently deduced as the action of the Wess-Zumino-Witten σ-model defined on the direct product of two N = 1, D = 10 Poincaré supertranslation groups. N = 2 supersymmetry of the action is shown to be related to a specific choice of the target manifold. We propose a zero curvature representation for the GS superstring field equations and interpret the local fermionic supersymmetry of the GS action as a guage symmetry preserving this representation.