Zakharov–Schulman system

In mathematics, the Zakharov–Schulman system is a system of nonlinear partial differential equations introduced in Zakharov & Schulman (1980) to describe the interactions of small amplitude, high frequency waves with acoustic waves. The equations are

${\displaystyle i\partial _{t}^{}u+L_{1}u=\phi u}$

${\displaystyle L_{2}\phi =L_{3}(|u|^{2})}$

where L₁, L₂, and L₃, are constant coefficient differential operators.