Generation of A High-Density, Axially Homogeneous Helicon Plasma for the AWAKE Wakefield Accelerator Project

该奖项支持一项新方法的研究，该方法利用等离子体作为加速介质，将粒子加速到非常高的能量。基本粒子加速到高能需要产生高电场，在电场中这些粒子可以达到接近光速的速度。在这个项目中，等离子体--一种带电粒子的电离气体--被用来产生非常强的电场，可以将粒子加速到如此高的速度。制造这种具有正确特征的等离子体的技术是独一无二的，涉及控制等离子体柱以使其在数百米内非常均匀。该项目旨在开发这项技术，并为欧洲核子研究组织(CERN)的一种新型粒子加速器的设计过程提供技术。该奖项支持研究生和本科生，包括合作学生到CERN设施的旅行。计划中的粒子加速器的等离子体产生需要利用被称为惠斯勒波的无线电波。这种被称为螺旋等离子体产生的方法是在几十年前开发的，众所周知，它可以非常高效地产生等离子体。在本项目中，Helcon等离子体源技术作为新一代粒子加速器技术在尾波场粒子加速中具有应用资格。建立了先进的基于激光的光谱方法来测量等离子体密度，并将其与最先进的波传播有限元建模和使用微波干涉仪和磁性探头测量这些特性结合使用。这些工作为欧洲核子研究中心的先进质子驱动等离子体尾场加速实验(ALAVE)项目设计等离子体源原型奠定了基础。觉醒计划的轴向等离子体密度分布必须均匀在0.25%以内，这是使用这种等离子体源所达到的前所未有的目标。如果成功，等离子体源将使下一代直线加速器的长度减少20-30倍，因此可能会对未来基于加速器的高能粒子物理研究的系统复杂性和成本产生重大影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports a study of a novel method to accelerate particles to very high energies using plasma as the accelerating medium. Acceleration of elementary particles to high energies entails creating high electric fields in which these particles can reach velocities close to the speed of light. In this project, a plasma - an ionized gas of electrically charged particles - is used to create very strong electric fields that can accelerate particles to such high velocities. The technology to create this plasma with the right features is unique and involves controlling the plasma column to make it very uniform for several hundred meters. The project aims to develop this technology and provide it for the design process for a new type of particle accelerator at the European Organization for Nuclear Research, known as CERN. The award supports graduate and undergraduate students, including collaborative student travel to the CERN facility. The plasma generation for the planned particle accelerator entails utilizing radio-frequency waves known as Whistler waves. This approach, called helicon plasma generation, was developed several decades ago and is known to create plasma with very high efficiency. In this project, the helicon plasma source technology is qualified for application in wakefield particle acceleration as a next-generation particle accelerator technology. Advanced, laser-based spectroscopic methods to measure plasma density are established and used together with state-of-the-art finite element modeling of the wave propagation and measurements of these characteristics using a microwave interferometer and magnetic probes. These efforts establish the basis for the design of a plasma source prototype for the Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) project at CERN. The axial plasma density profile for the AWAKE project has to be homogeneous within 0.25%, an unprecedented goal to reach with this plasma source. If successful, the plasma source will reduce the length of next-generation linear accelerators by a factor of 20-30, and hence may have a major impact on system complexity and cost for future accelerator-based high energy particle physics studies.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.