Structures and Electric Fields in Laser-Induced Magnetized Plasmas

电离气体或等离子体在自然界中普遍存在，例如在闪电、电离层、太阳和许多天体物理环境中。等离子体在气体放电灯、微制造工艺、聚变等离子体、内燃机和霍尔推进器等技术中也很常见。该项目将开发基于原子光谱学的新方法，以监测激光产生的实验室等离子体内部的电场和磁场。这一点很重要，因为众所周知，在不影响粒子分布和场的情况下，监测等离子体场是出了名的困难，特别是对于少量等离子体。这项研究将开创提供非侵入性等离子体诊断的新型量子技术。将研究等离子体中的激波阵面和有序结构，以及磁场对等离子体动力学的影响。由于等离子体在技术上的重要性，这样的等离子体物理研究推动了经济竞争力和繁荣、国防、空间探索和通信的进步。它还促进了基础等离子体科学和天体物理学的进步。参与该项目的学生将接受培训，帮助他们为在科学、工业和教育领域的职业生涯做准备。这项研究是关于通过激光诱导原子蒸气的光致电离而获得的小尺度、磁化的、潜在的强耦合的等离子体。将同时使用捕获原子和常温碱原子蒸汽室。随着光生等离子体的膨胀，它们形成激波阵面，在离子和电子之间的耦合足够强的情况下，等离子体有望发展出与晶体状有序的关联。这个项目将开创一种新的方法来对等离子体中的膨胀、激波阵面和有序结构进行位置和时间分辨测量。将利用里德堡原子的激光光谱学和电磁诱导透明(EIT)开发一种诊断方法。等离子体中的电场将通过里德伯格-EIT光谱分析来绘制。另一种诊断将使用微通道板来计数在可变延迟后从血浆中提取的颗粒。使用嵌入在等离子体中的场敏感里德堡态示踪原子作为等离子体中宏观和随机(Holtsmark)电场的全光学诊断可能会影响发生磁化等离子体的其他领域，例如在天体物理、惯性约束和磁约束聚变、Z-Pinch研究和离子捕获方面。从事这个项目的研究生和本科生将接受原子和等离子体物理研究、研究报告和同行指导方面的培训。学生还将获得科学仪器的建造和操作方面的经验。

Ionized gases, or plasmas, are ubiquitous in nature, for example in lightning, the ionosphere, the sun, and many astrophysical environments. Plasmas are also common in technologies such as gas discharge lamps, microfabrication processes, fusion plasmas, combustion engines, and Hall thrusters. This project will develop new methods based on atomic spectroscopy to monitor the electric and magnetic fields inside of laser-generated laboratory plasmas. This is important because plasma fields are notoriously difficult to monitor, especially for small volumes of plasma, without influencing the particle distributions and fields. The research will pioneer novel quantum technologies that provide non-invasive plasma diagnostics. Shock fronts and ordered structures in plasmas will be studied, as well as the effects of magnetic fields on plasma dynamics. Due to the importance of plasmas in technology, plasma-physics research such as this drives advances in economic competitiveness and prosperity, national defense, space exploration, and communications. It also promotes progress in basic plasma science and astrophysics. Students affiliated with this project will get training that will help them prepare for careers in science, industry and education. This study is on small-scale, magnetized, and potentially strongly-coupled, plasmas obtained by laser-induced photo-ionization of atomic vapors. Both trapped atoms and room-temperature alkali-atom vapor cells will be used. As the photo-generated plasmas expand, they form shock fronts, and in the case of sufficiently strong coupling between ions and electrons the plasmas are expected to develop correlations with crystal-like order. This project will pioneer novel ways to make position- and time-resolved measurements of the expansion, the shock fronts, and the ordered structures in plasmas. A diagnostic method will be developed using laser spectroscopy with Rydberg atoms and electromagnetically-induced transparency (EIT). Electric fields in the plasma will be mapped via Rydberg-EIT spectroscopy. Another diagnostic will use micro-channel plates to count particles that are extracted from the plasma after a variable delay. The use of field-sensitive Rydberg-state tracer atoms embedded in the plasma as an all-optical diagnostic of macroscopic and random (Holtsmark) electric fields in plasmas may impact other fields in which magnetized plasmas occur, for instance in astrophysics, inertial-confinement and magnetic-confinement fusion, z-pinch studies, and ion trapping. Graduate and undergraduate students working on this project will be trained in atomic and plasma physics research, research presentation, and peer instruction. Students will also gain experience in the construction and operation of scientific apparatus.