The generalised Kadomtsev-Petviashvili equations
u_t+u^pu_x+ u_{xxx}=\lambda \partial_x^{-1}u_{yy}, \quad p = 1,2, \dots
For π = 1, this is the KP I equation, for π = -1, this is the KP II equation. A blow-up of the solutions is possible for π β₯ 4/3.
The video above shows the time evolution of the initial data
u(x,y,0)=12\partial_{xx}\exp(-x^2-y^2)
for π = 4/3 and π = 1.
The second video shows the time evolution of the initial data
u(x,y,0)=6\partial_{xx}\exp(-x^2-y^2)
for π = 2 and π = 1.
References
See 1310.5215 for references and further details.