CAREER: The Impact of Electrons on Laboratory Plasma Jets of Astrophysical Relevance

这一职业奖支持在实验室环境中探索天体物理等离子喷流的形成和稳定性的基本物理学。天体物理喷流被认为是由超大质量黑洞将星际物质扫入喷流而产生的，将母黑洞的性质与喷流本身紧密地联系在一起。虽然黑洞很难观察到，但对于数百光年长的天体物理喷流来说，观测黑洞要容易得多。这项研究中以喷流形成为基准的模型可以精确确定产生天体物理喷流的黑洞质量，从而更好地了解暗物质在整个宇宙中的分布。虽然在实验室实验中找不到黑洞产生的深引力井，但有可能形成具有非常相似参数的高能量密度流。因此，可以在实验室使用天体物理流动的缩小版本来研究喷流形成的基本机制。这项研究工作还将包括并使包括高中生和本科生在内的学生沉浸在一个跨越许多科学学科和大陆的环境中，为他们提供高能量密度物理和等离子体天体物理的新视角。用来描述天体物理喷流动力学的典型假设往往过于简单化，往往忽略了电子在天体物理流动中的影响。虽然实验室实验不能再现黑洞的引力井，但它们仍然可以产生与天体物理相关的流。这项研究计划将研究电子对脉冲功率驱动器产生的湍流超音速射流的影响，重点放在三个关键问题上：(1)电子效应能否改善湍流射流的准直？(2)电子流是否可能成为宏观不稳定性的来源？以及(3)以脉冲功率实验为基准的物理模型能否推广到激光驱动的喷气式飞机，并最终推广到天体物理系统？这项研究中使用的诊断方法具有非凡的时间和空间精度，不仅可以测量空间和时间上的电子密度和磁场，还可以推断电子流动速度和电流。所有这四个量都将被用来测试广泛范围内的电子效应。这项研究的主要目标是清楚地展示电子效应在高能密度等离子体中何时何地发挥重要作用，以及这些效应如何一直扩展到天体物理系统。实验工作将在NSF重大研究仪器计划支持下建造的极端状态高安培驱动器(HADES)设施上进行。研究的多学科性质将使学生接触到不同的科学观点，并培养一个具有文化多样性的研究环境。通过指导、外展、招聘和海外经验，该计划将培训学生成为有效的导师和鼓舞人心的科学家。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 CAREER award supports exploration of the underlying physics of the formation and stability of astrophysical plasma jets in a laboratory setting. Astrophysical jets are thought to be generated by supermassive black holes sweeping interstellar matter into a jet, intimately connecting the properties of the parent black hole and the jet itself. While black holes are difficult to observe, it is much easier to do so for astrophysical jets that can be hundreds of light years in length. The jet formation models benchmarked in this research could allow for precise determination of masses of black holes that give rise to astrophysical jets, leading to a better understanding of the distribution of dark matter throughout the Universe. While the deep gravitational well created by a black hole is missing in laboratory experiments, it is possible to form high energy density flows with very similar parameters. Thus, the basic mechanisms of jet formation can be studied in the laboratory using scaled-down versions of astrophysical flows. This research effort will also include and immerse students, including high school and undergraduate students, in an environment crossing over many scientific disciplines and continents, giving them new perspectives in high energy density physics and plasma astrophysics. The typical assumptions used to describe astrophysical jet dynamics tend to be oversimplified and often ignore the impact of electrons in astrophysical flows. While laboratory experiments cannot reproduce the gravitational well of a black hole, they can still generate flows of astrophysical relevance. This research program will investigate the impact of electrons on turbulent, supersonic jets generated by pulsed-power drivers focusing on three key questions: (1) Can electron effects improve collimation of turbulent jets? (2) Is it possible for electron flows to be a source of macroscopic instabilities? and (3) Can the physics models benchmarked in pulsed-power experiments be carried over to laser-driven jets and, ultimately, to astrophysical systems? The exceptional temporal and spatial accuracy of the diagnostics to be used in this study will allow not only to measure the electron density and magnetic field across space and time, but to also infer the electron flow velocity and electrical currents. All four quantities will be used to test electron effects across a wide range of scales. The main goal of this research is to clearly demonstrate when and where electron effects play an important role in high energy density plasmas and how these effects scale all the way to astrophysical systems. The experimental work will be conducted on the High Amperage Driver for Extreme States (HADES) facility constructed with support from the NSF Major Research Instrumentation program. The multi-disciplinary nature of the research will expose students to different scientific perspectives and nurture a culturally diverse research environment. Through mentoring, outreach, recruitment and experience abroad, this program will train students in becoming effective mentors and inspired scientists.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.