Gray solitons on the surface of water

The dynamics of surface gravity water waves can be described by the self-defocusing nonlinear Schroedinger equation. Recent observations of black solitons on the surface of water confirmed its validity for finite, below critical depth. The black soliton is a limiting case of a family of gray soliton solutions with finite amplitude depressions. Here, we report observations of gray solitons in water waves, thus, complementing our previous observations of black solitons.