Relativistic plasma optics and collective particle dynamics in dense plasma

利用强激光等离子体相互作用中的相对论性现象，在带电粒子加速和高能辐射超短爆发的产生等应用方面取得了重大突破。即使是相对论性等离子体最基本的性质，比如它的折射率，也会受到电子运动非线性的深刻影响。强激光与等离子体之间的相互作用不仅改变了光的传播，而且决定了高能粒子和产生的辐射的性质。其中一种相对论性现象——诱导透明——可以产生激光自聚焦，传输具有快速上升边缘（通过薄箔）的较短脉冲，预计会改变激光的偏振。如果开发和控制，这些效应可以应用于强激光脉冲的主动操纵应用。我们最近已经证明，自产生的相对论等离子体孔径产生在薄箔经历透明，这引起了透射激光的衍射。由此产生的近场衍射图案横向置换等离子体电子，并可控制产生螺旋等离子体结构和其他集体电子运动。这个概念可以用来操纵电荷分离诱导的静电场，负责离子加速。该项目建立在这一工作计划的基础上，将提供对RSIT期间传输的激光辐射特性的新理解，从而巩固相对论等离子体光子学的发展，旨在实现超高强度和对比度下激光脉冲的可调谐时间、空间和偏振控制。这将包括在物理系苏格兰等离子体加速器应用中心（SCAPA）使用新的350TW最先进的激光器进行实验研究，以及在牛津郡中央激光设施使用外部更大规模的高功率激光设备。学生也有机会在正在开发的新极光基础设施（ELI）设施中为未来的实验做出贡献。该项目还包括对强激光等离子体相互作用现象的数值模拟，以帮助指导实验结果的解释。该项目的目标是：1。表征激光脉冲时间整形和选通2。确定激光聚焦空间强度分布的影响研究相对论透明诱导的激光偏振分布

Exploiting relativistic phenomena in intense laser-plasma interactions has led to significant breakthroughs in applications such as charged particle acceleration and the generation of ultra-short bursts of high energy radiation. Even the most fundamental properties of a relativistic plasma such as its index of refraction are profoundly affected by nonlinearities in electron motion. The interplay between intense laser light and the plasma not only modifies the light propagation, but also defines the properties of high energy particles and radiation produced.One such relativistic phenomena - induced transparency - can produce laser self-focusing, the transmission of shorter pulses with a fast rising edge (through thin foils) and is predicted to change the laser polarisation. If developed and controlled, these effects could be applied for the active manipulation of intense laser pulses for applications. We have recently shown that a self-generated relativistic plasma aperture is produced in a thin foil undergoing transparency, which induces diffraction of the transmitted laser light. The resulting near-field diffraction pattern transversely displaces plasma electrons and can be controlled to produce helical plasma structures and other collective electron motion. This concept can be used to manipulate the charge separation-induced electrostatic fields responsible for ion acceleration.The project builds on this programme of work and will provide new understanding of the properties of the laser radiation transmitted during RSIT and thus underpin the development of relativistic plasma photonics aimed at achieving tuneable temporal, spatial and polarisation control of laser pulses at ultrahigh intensity and contrast. This will include experimental investigations using the new 350TW state-of-the-art laser at the Scottish Centre for the Application of Plasma Accelerators (SCAPA) in the Physics department and external larger scale high power laser facilities at the Central Laser Facility in Oxfordshire. Opportunities also exist for the student to contribute to future experiments at the new Extreme Light Infrastructure (ELI) facilities under development. The project also involves numerical simulation of intense laser-plasma interaction phenomena to help guide the interpretation of experiment results.The objectives of the project are to:1. Characterise the laser pulse temporal shaping and gating2. Determine the influence of the laser focus spatial-intensity distribution 3. Investigate Relativistic transparency-induced laser polarisation distributions