Three dimensional (3D) wave group dynamics of ion acoustic wave is studied in electron–positron–ion (EPI) plasmas incorporating the effects of an external uniform magnetic field through the Laedke–Spatschek equation. In the presence of self-interaction (self-focusing effect), the wave group dynamics is shown to be governed by a (3 + 1) nonlinear Schrödinger equation. The derived nonlinear equations are solved analytically and the solutions predict a wide class of nonlinear structures in EPI plasma in the presence of magnetic field. The boundaries of stable and unstable solutions are also specified in parametric space. The results are expected to provide deeper insights into the ionic processes occurring in both astrophysical and laboratory plasmas.

中文翻译：

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外均匀磁场作用下电子-正电子-离子等离子体中离子声波的三维波群动力学

在电子-正电子-离子 (EPI) 等离子体中研究离子声波的三维 (3D) 波群动力学，通过 Laedke-Spatschek 方程结合外部均匀磁场的影响。在存在自相互作用（自聚焦效应）的情况下，波群动力学显示为由 (3 + 1) 非线性薛定谔方程控制。导出的非线性方程被解析求解，并且该解预测在存在磁场的情况下 EPI 等离子体中的多种非线性结构。稳定和不稳定解的边界也在参数空间中指定。预计这些结果将为天体物理和实验室等离子体中发生的离子过程提供更深入的见解。