New equations for the nonlinear interaction of long ion-acoustic waves and short langmuir waves in a plasma under benney’s resonance condition

The nonlinear interaction between long ion-acoustic waves and short Langmuir waves under Benney’s resonance condition is reanalysed on the basis of a two-fluid model for the plasma. The nonlinear equations thus found deviate from the ones commonly considered in the literature for this kind of interaction. The origin of this deviating result is discussed.