ULTRAfast exploration and control of electron bunch dynamics in SYNChrotron light sources

ULTRASYNC项目旨在观察，理解和控制加速器设施中相对论电子束团的超快自组织。一个中心目标是掌握同步辐射设施中同时发生的太赫兹（THz）相干同步辐射（CSR）巨脉冲的发射，从而提出新的THz源。另一个中间和主要的里程碑是设计新的超快观测工具（特别是高采集率的“太赫兹示波器”），这不仅是ULTRASYNC的迫切需要，而且也是加速器社区的普遍需求。该项目包括两个加速器设施的基础理论和实验研究：SOLEIL（FRA），法国国家光源，和KARA（格尔），KIT同步辐射源的电子储存环。该联盟的一个主要优势来自其最佳组成，这两个领导者在高重复率超快单次测量：KIT-LAS（格尔），其中主机在KARA的世界上唯一的实验之一，可以直接“探测”的形状相对论电子束在存储环设施，和SOLEIL-PhLAM合作（FRA）谁使用超快光子时间拉伸和时间成像技术。实验和理论/数值研究将与理解电子聚束的复杂和非线性动力学的目标并行进行。新获得的知识将用于尝试“驯服”CSR不稳定性，有两个雄心勃勃的战略：（i）在KARA，我们将直接操纵电子束之间的相互作用，通过开发实验EM场操纵结构，（ii）在SOLEIL，我们将尝试转移混沌控制技术（周期轨道的反馈控制），以实现稳定的THz CSR发射。该项目是跨学科的，因为它需要加速器物理学，非线性动力学（在储存环中，自发CSR发射来自不稳定性），混沌控制，激光和非线性光学的知识和能力。这将由激光，光子学，非线性动力学和加速器科学专家之间的密切互动提供。该项目的部分内容具有很高的风险，因为它们涉及的主要是未开发的研究领域，例如尖端探测技术，相对论粒子的非破坏性操纵以及极端复杂的不稳定性动力学。然而，由于组成了一个具有独特和互补的专门知识和历史的联营集团，这些风险是有限的。这些风险也在很大程度上被同步辐射界的潜在突破所抵消（用户在高功率下的稳定运行，以及高功率相干THz发射）。所获得的理解和超快采集技术是整个加速器物理界和其他领域的最大兴趣。

The ULTRASYNC project aims at observing, understanding and controlling ultrafast self-organisation of relativistic electron bunches in accelerator facilities. A central goal is to master the emission of giant pulses of terahertz (THz) Coherent Synchrotron Radiation (CSR) that occurs concomitantly in synchrotron radiation facilities and thus to propose new THz sources. Another intermediate and major milestone is to design novel ultrafast observation tools (in particular high acquisition rate “THz oscilloscopes”), which are critically needed - not only for ULTRASYNC - but also by the accelerator community in general. The project includes fundamental theoretical and experimental investigations at two accelerator facilities: SOLEIL (FRA), the French national light source, and KARA (GER), the electron storage ring of the KIT synchrotron radiation source. A main strength of the consortium comes from its optimal composition, both leaders in high repetition-rate ultrafast single shot measurements: KIT-LAS (GER), which hosts at KARA one of the only experiments in the world that can “probe” directly the shape of relativistic electron bunches in a storage ring facility, and the SOLEIL-PhLAM collaboration (FRA) who uses ultrafast photonic time-stretch and temporal imaging techniques. Experimental and theoretical/numerical investigations will be performed in parallel with the goal to understand the complex and non-linear dynamics of electron bunches. The newly acquired knowledge will be used for attempting to “tame” the CSR instabilities with two ambitious strategies: (i) at KARA, we will directly manipulate the interaction between electrons of the bunch, by developing experimental EM field manipulation structures, (ii) at SOLEIL, we will attempt to transfer techniques of chaos control (feedback control of periodic orbits), for achieving stable THz CSR emission. This project is interdisciplinary in nature, as it requires knowledge and capabilities in accelerator physics, non-linear dynamics (in storage rings, spontaneous CSR emission comes from instabilities), chaos control, laser and non-linear optics. This will be provided by a close interaction between specialists in laser, photonics, non-linear dynamics, and accelerator science. Parts of the project present a high level of risk, because they address largely unexplored research fields, such as cutting-edge detection techniques, non-destructive manipulation of relativistic particles, and dynamics of instabilities with extreme complexity. These risks are nevertheless limited by the formation of a consortium with unique and complementary know-how and history. These risks are also largely counterbalanced by the potential breakthroughs for the synchrotron radiation community (stable operation at high power for users, and high power coherent THz emission). The acquired understanding and the ultrafast acquisition techniques are of utmost interest to the entire accelerator physics community and beyond.