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会产生电离物质-等离子体。由于各种原因，这种等离子体正在世界范围内的实验室实验中进行研究。除了对等离子体性质的基本兴趣之外，激光等离子体可能导致重大技术突破。在这些可能的技术中，最重要的是通过聚变使用激光驱动的等离子体作为能源。核聚变提供了无限能源的前景，碳排放接近于零，没有长寿命的辐射废物。这将彻底改变世界能源市场，并可能为英国提供独立于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高科技产业从参与聚变科学中获益。美国的国家点火设施（NIF）正在朝着激光驱动聚变的目标取得重大进展，法国的一个类似规模的设施LaserMegaJoule（LMJ）也将很快完工。日本、法国、英国和美国正在寻求激光驱动聚变的替代方法。在世界范围内，这意味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中保持着领先的国际地位。为了保持这一地位，英国需要在理论和实验方面都具有国际竞争力。然而，对于NIF或LMJ的现场实验，必须首先对实验设计、激光器配置、目标特性和诊断进行模拟。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性质，并且至关重要的是，模拟了通过激光、等离子体压缩和加热产生的强电磁辐射场通过等离子体传输的能量。英国学术界没有这样的准则，因此有失去国际领先地位的危险。这项建议是开发一个能够设计聚变芯块、诊断和先进聚变点火方案的辐射-流体动力学代码（Odin）。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。奥丁还将直接应用于激光等离子体物理学的其他分支。目前正在进行和计划中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，但存在降低所需设备的成本和尺寸并具有更多控制的潜力。优化这种激光加速器的关键是理解在主激光脉冲到达之前首先在靶前形成的等离子体。这种所谓的预等离子体不能很容易地通过实验测量，但它可以通过Odin代码精确地模拟。因此，奥丁将直接有助于基于激光等离子体的质子加速器的研究。预等离子体对于超高功率激光实验来说也是一个严重的问题，例如欧盟资助的极光基础设施（ELI），其目标是进入QED等离子体体系。英国研究人员将使用Odin代码数十年。因此，至关重要的是，这种代码是可持续的，并适应新兴的硬件在高性能计算。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，以确保其针对当前和下一代计算机进行优化，并受益于物理学和计算机科学的进步。英国等离子体物理计算合作项目（CCPP）将管理整个项目，并向所有英国等离子体研究人员提供代码。

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.