Fast ignition inertial confinement fusion requires the production of a low-density channel in plasma with density scale-lengths of several hundred microns. The channel assists in the propagation of an ultra-intense laser pulse used to generate fast electrons which form a hot spot on the side of pre-compressed fusion fuel. We present a systematic characterization of an expanding laser-produced plasma using optical interferometry, benchmarked against three-dimensional hydrodynamic simulations. Magnetic fields associated with channel formation are probed using proton radiography, and compared to magnetic field structures generated in full-scale particle-in-cell simulations. We present observations of long-lived, straight channels produced by the Habara–Kodama–Tanaka whole-beam self-focusing mechanism, overcoming a critical barrier on the path to realizing fast ignition. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

中文翻译：

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聚变相关等离子体中的全光束自聚焦

快速点火惯性约束聚变需要在等离子体中产生一个密度尺度长度为几百微米的低密度通道。该通道有助于超强激光脉冲的传播，用于产生快速电子，在预压缩聚变燃料的一侧形成热点。我们使用光学干涉测量法对膨胀的激光产生的等离子体进行系统表征，以三维流体动力学模拟为基准。使用质子射线照相术探测与通道形成相关的磁场，并与全尺寸粒子细胞模拟中产生的磁场结构进行比较。我们展示了由 Habara-Kodama-Tanaka 全光束自聚焦机制产生的长寿命直通道的观察结果，克服实现快速点火道路上的关键障碍。本文是讨论会议问题“高增益惯性聚变能的前景（第 2 部分）”的一部分。