Graduate Student Training through Research on Plasma-Based Accelerators

自2009年9月1日以来，美国国家科学基金会合作资助的“通过等离子体加速器研究培养研究生”项目已经资助了7个不同机构的14名研究生的工作。其中8名学生已经毕业，另外6名预计将于2014年9月毕业。这个项目支持这六名学生中的一名，他的科学目标是可视化——在一次拍摄中——在强烈的超短激光脉冲或电子束之后以光速传播的不断发展的等离子体结构。通过本研究开发和完善的单次频域全息（FDH）可视化和控制技术可以通过对激光等离子体加速器（LPA）的影响来影响等离子体和加速器科学的广泛领域。在LPA科学中，FDT将从根本上为LPA扩展到多gev能量做出贡献。紧凑的FDT系统最终可能成为未来激光和质子驱动等离子体加速器的标准在线计量系统，这些加速器可以产生高达能量前沿的电子。这些方法还将促进更可靠的基于等离子体的加速器，这些加速器可作为紧凑、相干的x射线源用于生物、化学和医学研究，可用于常规加速器的注射器和医用加速器。该学生将应用并适应PI实验室开发的频域全息（FDH）前沿可视化方法来解决新的前沿等离子体科学问题：(1)他将在两种情况下实现激光驱动等离子体气泡的FDT可视化：(a)由超短太瓦激光脉冲驱动的大气密度等离子体；(b)由德克萨斯千兆瓦激光器驱动的0.01大气压等离子体，目的是了解、优化和扩展激光等离子体加速器（LPA），该加速器最近将电子加速到创纪录的2 GeV能量。细胞内粒子和光子模拟将指导实验。他将开发适合于在一米长的纤细等离子体中观察尾迹的方法。设计这些方法的目的是最终在先进的加速器设施中实施，例如SLAC的加速器科学和实验测试设施（FACET）。

The NSF Collaborative grant "Graduate Student Training through Research on Plasma-Based Accelerators", has supported the work of 14 graduate students since September 1, 2009 at seven different institutions. Eight of these students have already graduated and another six are expected to graduate by September 2014. This project supports one of these six students, whose scientific goal is to visualize --- in a single shot --- evolving plasma structures that propagate at the speed of light in the wake of intense ultrashort laser pulses or electron bunches. The single-shot Frequency Domain Holography (FDH) visualization and control techniques developed and refined through this research can impact a wide cross section of plasma and accelerator science through the impact on Laser Plasma Accelerators (LPA). In LPA science, FDT will contribute fundamentally to scaling LPAs to multi-GeV energy. Compact FDT systems could ultimately become standard in-line metrology for future laser- and proton-driven plasma accelerators that produce electrons up to the energy frontier. These methods will also promote more reliable plasma-based accelerators, which are useful as compact, coherent x-ray sources for biological, chemical, and medical research, injectors for conventional accelerators, and medical accelerators. The student will apply and adapt the Frequency Domain Holography (FDH) cutting-edge visualization method developed in the PI's laboratory to new frontier plasma science problems: (1) He will implement FDT visualization of evolving laser-driven plasma bubbles in two regimes: (a) atmospheric density plasma driven by an ultrashort terawatt laser pulse; (b) 0.01 atmosphere plasma driven by the Texas Petawatt Laser, with the aim of understanding, optimizing and scaling a laser-plasma accelerator (LPA) that recently accelerated electrons to a world-record-breaking energy of 2 GeV. Particle-in-cell and photon-in-cell simulations will guide the experiments. (2) He will develop methods suitable for visualizing wakes in meter-long tenuous plasma. These methods will be designed with the intention of implementing them ultimately at advanced accelerator facilities such as SLAC's Facility for Accelerator Science and Experimental Tests (FACET).