CCP Flagship: A radiation-hydrodynamics code for the UK laser-plasma community

高功率激光与固体的相互作用产生电离物质——等离子体。由于各种原因，这种等离子体正在世界各地的实验室实验中进行研究。除了对等离子体本质的基本兴趣之外，激光等离子体可能会带来重大的技术突破。在这些可能的技术中，最重要的是利用激光驱动的等离子体作为核聚变的能量来源。核聚变提供了无限能源的前景，几乎零碳排放，没有长寿命的放射性废物。这将彻底改变世界能源市场，并有可能为英国确保不依赖进口的基本负荷能源供应。此外，保持英国在这一领域的领先地位也将使英国的高科技产业从参与核聚变科学中获利。美国的国家点火装置（NIF）正在朝着激光驱动核聚变的目标取得重大进展，法国的一个类似规模的装置LaserMegaJoule （LMJ）即将完工。日本、法国、英国和美国正在研究激光驱动核聚变的替代方法。在全球范围内，这代表着数十亿美元的投资。英国等离子体科学家在这些理论和实验发展方面一直处于国际领先地位。为了保持这种领先地位，英国需要在理论和实验方面都具有国际竞争力。然而，在NIF或LMJ的现场实验中，必须首先模拟实验设计、激光配置、目标特性和诊断。这需要一种特殊形式的流体模拟代码，称为辐射流体动力学代码。这些代码模拟了流体状等离子体的特性，最关键的是，通过激光、等离子体压缩和加热产生的强电磁辐射场在等离子体中传输的能量。英国学术界没有这样的准则，因此有可能失去其国际领先地位。该提案旨在开发一种能够设计聚变球团、诊断和推进聚变点火方案的辐射流体动力学代码（Odin）。核聚变研究所需的辐射流体动力学代码类型将基于一种称为任意拉格朗日欧拉（ALE）的方案。开发Odin ALE代码是一项重大任务。奥丁也可以直接应用于激光等离子体物理的其他分支。正在进行和计划的实验旨在产生用于医疗的质子和碳束。这种离子束疗法现在是可能的，但还存在降低所需设备的成本和尺寸以及更多控制的潜力。优化这种激光加速器的关键是了解在主要激光脉冲到达之前首先在目标前方形成的等离子体。这种所谓的预等离子体不容易通过实验测量，但可以通过奥丁代码精确地模拟出来。因此，奥丁将直接为基于激光等离子体的质子加速器的研究做出贡献。预等离子体也是非常高功率激光实验的一个严重问题，例如欧盟资助的极端光基础设施（ELI），其目标是进入qed等离子体状态。奥丁密码将被英国研究人员使用数十年。因此，这些代码必须是可持续的，并且能够适应高性能计算中的新兴硬件。因此，计算机科学家和等离子体物理学家将合作开发Odin代码，以确保它针对当前和下一代计算机进行优化，并从物理学和计算机科学的进步中受益。英国等离子体物理计算合作项目（CCPP）将管理整个项目，并将代码提供给所有英国的等离子体研究人员。

The interaction of high-power lasers with solids generates an ionised material - a plasma. Such plasmas are being studied in laboratory experiments worldwide for a variety of reasons. Beyond this fundamental interest in the nature of plasmas is the possibility that laser-plasmas may lead to technological breakthroughs of significant importance. Foremost amongst these possible technologies is using laser-driven plasmas as a source of energy via fusion. Fusion offers the prospect of limitless energy with near zero carbon emission and no long-lived radiative waste. This would revolutionise the world energy markets and potential secure a base load energy supply for the UK independent of imports. Additionally maintaining a UK lead in this field also would allow UK high-tech industries to profit from involvement in fusion science.The National Ignition Facility (NIF) in the US is making significant progress towards the goal of laser-driven fusion and a similar size facility in France, the LaserMegaJoule (LMJ), will soon be completed. Alternative approaches to laser-driven fusion are being pursued in Japan, France, UK and USA. Worldwide this represents billions of dollars of investment. UK plasma scientists have maintained a leading international role in these theoretical and experimental developments. In order to maintain that roll the UK needs to be internationally competitive in both theory and experiments. However to field experiments on NIF or LMJ the design of the experiment, laser configuration, target properties and diagnostics must all be simulated first. This requires a special form of fluid simulation code called a radiation-hydrodynamics code. Such codes model the properties of the fluid-like plasma and, crucially, the energy transported through the plasma via the strong electromagnetic radiation field resulting from the laser, plasma compression and heating. UK academia has no such code and is in danger of loosing its international lead as a result. This proposal is to develop a radiation-hydrodynamics code (Odin) capable of designing fusion pellets, diagnostics and advance fusion ignition schemes. The type of radiation-hydrodynamics code that is needed for fusion research would be based around an scheme called Arbitrary Lagrangian Euler (ALE). Developing the Odin ALE code is a major undertaking. Odin would also have direct applications to other branches of laser-plasma physics. There are experiments being run, and planned, which aim to generate proton and carbon beams for medical treatments. Such ion-beam therapy is possible now but the potential exists to reduce the cost and size of equipment needed and have more control. Crucial to optimising such laser accelerators is an understanding of the plasma that first forms in front of the target before the main laser pulse arrives. This so called pre-plasma cannot be easily measured experimentally but it could be accurately simulated by the Odin code. Thus Odin would directly contribute to research in laser-plasma based proton accelerators. Pre-plasmas are also a serious issue for very high-power laser experiments, such as the EU funded Extreme Light Infrastructure (ELI), which aim to access the QED-plasma regime.The Odin code will be used for decades by UK researchers. It is therefore essential that this code is sustainable and adaptable to the emerging hardware in high-performance computing. Computer scientists, as well as plasma physicists, will therefore collaborate in the development of the Odin code to ensure it is optimised for current and next generation computers and benefits from the advances in both physics and computer science. The UK Computational Collaborative Project in Plasma Physics (CCPP) will manage the whole project and the code made available to all UK based plasma researchers.