Compound WKI-SP hierarchy and multiloop soliton solutions

Abstract

The generalized hierarchies of compound WKI-SP (Wadati-Konno-Ichikawa and short pulse) equations are presented. The proposed integrable nonlinear equations include the WKI-type equations, the SP-type equations and the compound generalized WKI-SP equations. A chain of hodograph transformations are established to relate the compound WKI-SP equations with the MKdV-SG (modified Korteweg-de Vries and sine-Gordon) equations. As applications, the multiloop soliton solutions of one compound WKI-SP equation are obtained. We emphasize on showing abundant solitonic behaviors of two loop solitons. The role of each parameter plays in the movement of two-loop solion are shown detailedly in a table.