The dynamics of coupled ion-acoustic waves is investigated in an electronegative plasma made of Boltzmann negative ions, cold mobile positive ions and Boltzmann electrons. Using the reductive perturbation method, it is shown that the system can fully be described by a set of two coupled nonlinear Schrodinger equations. The parametric analysis of modulational instability reveals the existence of regions of instability that are sensitive to changes in plasma parameters such as the negative ion concentration ratio and the electron-to-negative ion temperature ratio. The analytical results are confronted to numerical simulations, where we examine the long-time dynamics of modulated waves in the electronegative plasma. One obtains the generation of nonlinear modulated waves that are sensitive to the negative-ion concentration ratio. Exact solutions for individual modes are discussed and one finally derives the coupled solution. The response of the latter to the plasma parameter variations is also addressed.

中文翻译：

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电负性等离子体中耦合波的调制不稳定性

在由玻尔兹曼负离子、冷移动正离子和玻尔兹曼电子组成的负电等离子体中研究了耦合离子声波的动力学。使用还原微扰方法，表明系统可以完全由一组两个耦合的非线性薛定谔方程来描述。调制不稳定性的参数分析揭示了不稳定区域的存在，这些区域对等离子体参数的变化很敏感，例如负离子浓度比和电子与负离子温度比。分析结果面临着数值模拟，在那里我们检查了带负电等离子体中调制波的长期动力学。一种是产生对负离子浓度比敏感的非线性调制波。讨论了各个模式的精确解，最后推导出耦合解。后者对等离子体参数变化的响应也得到了解决。