A modified nonlinear Schrodinger equation, governing the behaviour of nonlinear ion accoustic waves in a plasma with density gradient, is derived by the Krylov-Bogoliubov-Mitropolsky pertubation method.

• 本文用Krylov-Bogoliubov-Mitropolsky微扰法得出了控制具有密度梯度等离子体中的离子声波的修正非线性Schr(?) dinger方程。