Optical Visualization of Beam-driven Plasma Wakefield Accelerators

光束驱动等离子体韦克场加速器的光学可视化

• 批准号: 2010435
• 负责人: Michael Downer
• 金额: $ 54.51万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2010435&HistoricalAwards=false
• 关键词: Optical; Visualization; Beam; driven; Plasma

This research project aims to create and diagnose pliable, microscopic structures made of ionized gas, or "plasma", that are suitable for accelerating, shaping and bunching beams of electrons and their antimatter twins called "positrons" far more compactly and cheaply than conventional accelerators. Nearly all of the world's 30,000 conventional particle accelerators, which serve industry, hospitals and discovery science, accelerate ordinary matter particles, such as electrons and protons. A mere handful of mega-facilities accelerate parallel matter/antimatter particle beams - such as electrons and positrons, or protons and anti-protons. When collided with each other, such twin beams yield a treasure trove of new particles, with exotic names like "W", "Z" and "Higgs" bosons, which have reaped several Nobel prizes. Unfortunately, the technology underlying such past breakthroughs has become too large and expensive to support new breakthroughs. In this project, an energetic electron bunch racing through a pipe filled with lithium gas creates and energizes short-lived plasma filaments only a yard long, and thinner than a human hair, just as a boat racing across a pond creates a wake. This "wake" can accelerate both electrons and positrons to the same energy as a mile-long conventional accelerator as wide as an 18-wheeler. Computer simulations show that the part of the plasma wake 1/1000 inch behind the electron “boat” is a good electron accelerator, whereas the part one inch behind is a good positron accelerator. Flash holograms of these parts of the wake test the simulations. Moreover, carefully timed electron and positron bunches can be surfed on the wake, to test its viability as an accelerator directly. Success could lead not only to compact, affordable technology for future particle physics discoveries, but to new medical and industrial applications of positron imaging that take advantage of the unique intensity, narrowness and energy uniformity of positron beams from accelerators.The 3-year project carries out approved experiment E-324 "Optical visualization of beam-driven plasma wakefield accelerators" at the 2nd generation SLAC Facility for Advanced Accelerator Science and Experimental Tests (FACET-II). FACET-II's 10 GeV electron bunches drive strongly nonlinear plasma wakes in a meter-long lithium plasma of density 10^17 electrons per cm^3. A 100 fs, near-infrared, near-co-propagating optical probe pulse, synchronized with the electron bunch, impinges on the bunch's path at grazing angle at time delays ranging from 0 to 50 ps, and diffract from the wake. Downstream detectors record the probe's diffraction pattern, from which the wake's evolving electron density profile can be reconstructed and compared to predictions of computer simulations. Scientific goals are: (1) to observe a sharp on-axis ion density peak that computer simulations predict to form at ~50 ps; (2) to excite and diagnose an electron wake in this ion density structure with a secondary electron bunch, and to test its predicted suitability for stable positron acceleration; (3) to observe the bubble-shaped electron wake at delays below 1 ps behind the primary electron bunch, which is well suited for accelerating electrons, for the first time. The intellectual merit consists in observing particle-beam-driven plasma wakes for the first time, and in creating and identifying complementary plasma structures suitable for electron and positron acceleration, thereby paving the way for a dual plasma-based electron-positron accelerator. The broader impacts include development of compact, affordable accelerator technology and training of the next generation workforce, including graduate and undergraduate students with diverse backgrounds.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该研究项目旨在创建和诊断由电离气体或“等离子体”制成的柔韧的微观结构，这些结构适用于加速，成形和聚集电子束及其反物质双胞胎（称为“正电子”），比传统加速器更复杂，更便宜。世界上几乎所有的30，000个传统粒子加速器，服务于工业，医院和发现科学，加速普通物质粒子，如电子和质子。只有少数大型设施加速平行的物质/反物质粒子束-例如电子和正电子，或质子和反质子。当这种双光束相互碰撞时，就会产生一个新粒子的宝库，它们有着奇特的名字，比如“W”、“Z”和“希格斯”玻色子，这些粒子已经获得了几项诺贝尔奖。不幸的是，过去这些突破背后的技术已经变得过于庞大和昂贵，无法支持新的突破。在这个项目中，一个充满能量的电子束在充满锂气体的管道中运动，产生并激发了寿命很短的等离子体细丝，这些细丝只有一码长，比人的头发丝还细，就像一艘船在池塘中运动时产生的尾迹一样。这种“尾流”可以将电子和正电子加速到与一英里长的常规加速器一样宽的能量。计算机模拟表明，等离子体尾流在电子“船”后面1/1000英寸的部分是一个很好的电子加速器，而后面1英寸的部分是一个很好的正电子加速器。这些尾流部分的闪光全息图测试了模拟结果。此外，仔细定时的电子和正电子束可以在尾流上冲浪，以直接测试其作为加速器的可行性。成功不仅可以为未来的粒子物理发现带来紧凑，负担得起的技术，而且可以利用正电子成像的独特强度，这个为期3年的项目执行经核准的实验E-324“束流驱动等离子体韦克菲尔德加速器的光学可视化”第二代SLAC先进加速器科学和实验测试设施（FACET-II）。FACET-II的10 GeV电子束在一米长、密度为10^17个电子/cm ^3的锂等离子体中驱动强烈的非线性等离子体尾流。与电子聚束同步的100 fs、近红外、近共传播光学探测脉冲以掠射角撞击聚束路径，时间延迟范围为0至50 ps，并从尾流中衍射。下游探测器记录探测器的衍射图案，从中可以重建尾流的演变电子密度分布，并与计算机模拟的预测进行比较。科学目标是：（1）观察计算机模拟预测在~50 ps处形成的尖锐的轴上离子密度峰值;（2）用二次电子聚束激发和诊断该离子密度结构中的电子尾流，并测试其预测的稳定正电子加速的适用性;（3）首次观测到了延迟小于1 ps的气泡状电子尾流，这是一种非常适合加速电子的电子尾流。其智力价值在于首次观察到粒子束驱动的等离子体尾流，并创造和识别适合电子和正电子加速的互补等离子体结构，从而为基于双等离子体的电子-正电子加速器铺平道路。更广泛的影响包括开发紧凑，负担得起的加速器技术和培训下一代劳动力，包括具有不同背景的研究生和本科生。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

2020 roadmap on plasma accelerators

• DOI: 10.1088/1367-2630/abcc62
• 发表时间: 2021-03-01
• 期刊: NEW JOURNAL OF PHYSICS
• 影响因子: 3.3
• 作者: Albert, Felicie;Couprie, M. E.;Zeil, Karl
• 通讯作者: Zeil, Karl

Faraday rotation study of plasma bubbles in GeV wakefield accelerators

• DOI: 10.1063/5.0072262
• 发表时间: 2021-09
• 期刊: Physics of Plasmas
• 影响因子: 2.2
• 作者: Yen-Yu Chang;Xiantao Cheng;A. Hannasch;M. LaBerge;J. Shaw;K. Weichman;J. Welch;A. Bernstein;W. Henderson;R. Zgadzaj;M. Downer

Ion dynamics driven by a strongly nonlinear plasma wake

由强非线性等离子体尾流驱动的离子动力学

• DOI: 10.1088/1361-6587/ac4523
• 发表时间: 2022
• 期刊: Plasma Physics and Controlled Fusion
• 影响因子: 2.2
• 作者: Khudiakov, V K;Lotov, K V;Downer, M C
• 通讯作者: Downer, M C