Special derivative nonlinear Schrödinger (DNLS) systems exhibiting 2-soliton solutions

Various versions of the derivative nonlinear Schrödinger (DNLS) equation occur frequently in applied science. Modified DNLS systems with fifth order nonlinearity are studied here via the Hirota bilinear transformation. 2-Soliton solutions are constructed as a preliminary signal for the special nature of the partial differential equations. Cases treated include a (2+1) (2 spatial and 1 temporal)-dimensional system, an equation incorporating third order dispersion, and a coupled (multi-component) system. Relevance and potential applications to hydrodynamics and fiber optics are discussed.