title: Zakharov–Schulman system
text: # 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
  
      $i\partial _{t}^u+L_{1}u=\phi u$
      $L_{2}\phi =L_{3}(|u|^{2})$
  
  where $L_1,$ $L_2,$ and $L_3,$ are constant coefficient differential operators.
  
  