Ouatu I, Spiers B T, Aboushelbaya R, Feng Q, von der Leyen M W, Paddock R W, Timmis R, Ticos C, Krushelnick K M, Norreys P A
Department of Physics, Atomic and Laser Physics sub-Department, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Central Laser Facility, UKRI-STFC Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, United Kingdom.
Phys Rev E. 2022 Jul;106(1-2):015205. doi: 10.1103/PhysRevE.106.015205.
A paradigm shift in the physics of laser-plasma interactions is approaching with the commissioning of multipetawatt laser facilities worldwide. Radiation reaction processes will result in the onset of electron-positron pair cascades and, with that, the absorption and partitioning of the incident laser energy, as well as the energy transport throughout the irradiated targets. To accurately quantify these effects, one must know the focused intensity on target in situ. In this work, a way of measuring the focused intensity on target is proposed based upon the ionization of xenon gas at low ambient pressure. The field ionization rates from two works [Phys. Rev. A 59, 569 (1999)1050-294710.1103/PhysRevA.59.569 and Phys. Rev. A 98, 043407 (2018)2469-992610.1103/PhysRevA.98.043407], where the latter rate has been derived using quantum mechanics, have been implemented in the particle-in-cell code SMILEI [Comput. Phys. Commun. 222, 351 (2018)0010-465510.1016/j.cpc.2017.09.024]. A series of one- and two-dimensional simulations are compared and shown to reproduce the charge states without presenting visible differences when increasing the simulation dimensionality. They provide a way to accurately verify the intensity on target using in situ measurements.
随着全球多拍瓦激光装置的投入使用，激光与等离子体相互作用物理学正迎来一场范式转变。辐射反应过程将引发电子 - 正电子对级联反应，进而导致入射激光能量的吸收与分配，以及能量在整个被辐照靶体中的传输。为准确量化这些效应，必须原位了解靶体上的聚焦强度。在这项工作中，提出了一种基于低环境压力下氙气电离来测量靶体上聚焦强度的方法。来自两篇论文[《物理评论A》59, 569 (1999)1050 - 294710.1103/PhysRevA.59.569和《物理评论A》98, 043407 (2018)2469 - 992610.1103/PhysRevA.98.043407]的场电离率已被应用于粒子模拟程序SMILEI[《计算机物理通讯》222, 351 (2018)0010 - 465510.1016/j.cpc.2017.09.024]中，其中后者的电离率是使用量子力学推导出来的。一系列一维和二维模拟结果进行了比较，结果表明，在增加模拟维度时，电荷态的再现没有明显差异。它们提供了一种通过原位测量来准确验证靶体上强度的方法。
