The development of a self-sustained quantum electrodynamical (QED) cascade in a single strong laser pulse is studied analytically and numerically. A hydrodynamical approach is used to construct an analytical model of cascade evolution, which includes the key features of the cascade observed in 3D QED particle-in-cell (QED-PIC) simulations, such as the magnetic field dominance in the cascade plasma and laser energy absorption. The equations of the model are derived in closed form and solved numerically. Direct comparison between the solutions of the model equations and 3D QED-PIC simulations shows that our model is able to describe the complex nonlinear process of cascade development qualitatively well. Various regimes of the interaction based on the intensity of the laser pulse are revealed in both the solutions of the model equations and the results of the QED-PIC simulations.

中文翻译：

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极强激光脉冲中QED级联膨胀的流体力学模型

分析和数值研究了单个强激光脉冲中自持量子电动力学（QED）级联的发展。使用流体力学方法来构建级联演化的分析模型，其中包括在3D QED单元内粒子（QED-PIC）模拟中观察到的级联的关键特征，例如级联等离子体和激光中的磁场优势能量吸收。该模型的方程以封闭形式导出并通过数值求解。模型方程解与3D QED-PIC仿真的直接比较表明，我们的模型能够很好地定性描述级联发展的复杂非线性过程。