Harnessing laser-driven plasma waves as particle and radiation sources

我们建议在ALPHA-X项目成功的基础上，开展一项新的研究计划，研究和开发明确利用激光驱动等离子体波的新型紧凑型辐射源。该项目将推动尾流场加速器的发展，并利用在等离子体通道中加速的10秒以下电子束，在自由电子激光器和相干辐射体结构中产生相干红外至x射线的超短脉冲。主要目标将是通过利用等离子体波的极短空间周期波状结构来推动硬x射线和伽马射线，从而在迄今为止无法进入的光谱区域奠定源的基础。我们还将通过以下方式推动超短脉冲产生的前沿：I)使用预聚束技术控制和减少来自韦克菲尔德加速器的电子束持续时间，这也将增加可用的峰值电流，同时减少来自辐射源的脉冲长度；ii)通过反向散射来自相对论性等离子体尾迹和电离锋形成的相对论性镜子的定制太赫兹脉冲，研究任意形状单周期脉冲的产生和裁剪（最初在可见光中）。开发这些新型紧凑型辐射源的实验计划将利用在ALPHA-X项目下建立的斯特拉斯克莱德的独特设施，以及欧盟、美国和中国的可用资源，提供长期开发计划和短期（6周）活动的组合，利用设施中可用的特定激光束特性。该项目的一个重要方面将是一个实质性的理论计划，该计划将由先前在ALPHA-X下共同工作的理论团队和带来新方法和背景的新团队来承担重大理论挑战。大批合作者为方案提供了广度和深度，通过他们的贡献和利用他们的各种设施，也将能够非常有效地利用资源。该研究项目是英国路线图的核心，概述了该领域潜在的新景观和前进方向。

We propose to build on the successes of the ALPHA-X project with a new programme of research to investigate and develop novel compact radiation sources that explicitly exploit laser-driven plasma waves. The project will take forward the development of wakefield accelerators and utilise the sub-10 fs electron bunches accelerated in plasma channels to produce ultra-short pulses of coherent infrared to x-ray radiation in a FEL and coherent radiator structures. The main objective will be to push towards hard x-rays and gamma rays by utilising the very short spatial period undulator-like structures of plasma waves to lay down the foundations of sources in a spectral region hitherto not accessible. We will also push the frontiers of ultra-short pulse generation by: i) controlling and reducing the electron bunch duration from wakefield accelerators using pre-bunching techniques, which will also increase the peak current available while reducing the pulse length from a radiation source, and by ii) investigating the generation and tailoring of arbitrary shaped single-cycle pulses (initially in the visible) by backscattering tailored terahertz pulses from relativistic mirrors formed by relativistic plasma wakes and ionisation fronts. The experimental programme to develop these novel compact radiation sources will utilise the unique facilities at Strathclyde, set up under the ALPHA-X project, and resources available in the EU, US and China, to provide a mix of long-term development programmes and short-term (6-week) campaigns that take advantage of the particular laser beam characteristics available at the facilities. An important aspect of the project will be a substantial theoretical programme that will be undertaken by an established team of theoreticians that has previously worked together under ALPHA-X, and new teams that bring new approaches and backgrounds to bear on the significant theoretical challenges. The large group of collaborators provide both breadth and depth to the programme, and through their contributions and access to their various facilities, will also enable very effective use of resources. The programme of research is central to a UK roadmap that outlines potential new landscapes and ways forward in the field.