Instabilities in non-thermal plasmas

非热等离子体中的不稳定性

• 批准号: EP/G04239X/1
• 负责人: Kevin Ronald
• 金额: $ 130.76万
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG04239X%2F1
• 关键词: Instabilities; non; thermal; plasmas

It is important to understand instabilities in plasmas since these play a crucial role in the behaviour of schemes for controlled nuclear fusion, the performance of devices for generating high power radiation and in phenomena taking place in the earth's magnetosphere, stars and more exotic astrophysical objects. In many cases these instabilities are generated by beams of high energy electrons, and the main objective of the present work is to study such beam driven instabilities in a laboratory experiment and support this study through detailed theoretical and computational analysis. This research builds on the foundation of our earlier work which concentrated on an instability of relevance to the onset of parasitic oscillations in powerful radiation sources, to auroral radio emissions and a variety of other astrophysical phenomena. Experimental results showed good agreement with the observations of auroral radiation and with theory. Now the range of the research is being significantly extended to an ambitious programme aimed at the study of a variety of instabilities driven by different distributions of energetic electrons in varying experimental geometries. This entails substantial modifications of the original experimental facility to introduce extra flexibility in the generation of the fast electrons, modifications to the magnetic field structure which guides them and the introduction of a background plasma.We will generate well-controlled plasmas in which the growth and eventual saturation of the unstable oscillations can be studied in detail. The results will be compared with computer simulations and with theoretical modelling with a view to checking their accuracy. We will investigate different aspects of these instabilities relevant to a range of applications including for example tokamaks. In these toroidal devices which confine plasmas are hoped to reach fusion conditions, schemes for radiofrequency driving of current produce an important population of electrons with a high velocity and energy. The stability of these populations and how they evolve in response to instabilities needs to be understood. In schemes for fusion involving laser compressed targets, beams of fast electrons moving into the central region of the target are very important and the understanding of their behaviour is largely based on computer simulation. The relation between simulation results and reality will be more easily seen in our large scale experiment. Generation of high power RF radiation, which has a wide range of applications ranging from RaDAR to medical treatment, largely depends on the instability of high power electron beams and the conversion of their energy into electromagnetic waves. Our work should give an enhanced understanding on some of these processes, in particular on the production of parasitic radiation from unintended instabilities. Finally, beams of high energy particles are very common in space and astrophysical plasmas, ranging from the earth's magnetosphere to pulsars and gamma ray bursters. The understanding of the basic physics of instabilities derived from this research will give confidence in the application of theoretical and numerical techniques to other real plasma environments, including Fusion experiments.The project brings together a team with extensive expertise in experimental beam plasma systems, together with wide experience in theory and computational modeling applied to magnetically confined plasma, laser produced plasma and space plasma. The experiment, designed to allow the investigation of a wide range of conditions and to isolate particular instabilities of direct importance to magnetic and inertial fusion schemes and high power radiation generation.

重要的是要了解等离子体中的不稳定性，因为这些在受控核融合方案的行为中起着至关重要的作用，在地球磁层，恒星和更多外来的天文学物体中，产生高功率辐射的设备的性能以及发生的现象。在许多情况下，这些不稳定性是由高能电子的光束产生的，目前工作的主要目的是在实验室实验中研究此类梁驱动的不稳定性，并通过详细的理论和计算分析来支持这项研究。这项研究基于我们较早的工作的基础，该研究集中于与强大的辐射源中寄生振荡发作相关的不稳定性，与极光无线电排放以及其他各种天体物理现象相关。实验结果表明，与极光辐射的观察以及理论相吻合。现在，这项研究的范围已大大扩展到旨在研究各种不稳定性的雄心勃勃的计划，该计划是由不同实验几何形状中能量电子的不同分布驱动的。这需要对原始实验设施进行实质性修改，以引入快速电子的生成，对引导它们的磁场结构的修改以及引入背景等离子体的引入。我们将详细研究不稳定的振动的生长和最终饱和的等离子体。结果将与计算机模拟和理论建模进行比较，以检查其准确性。我们将研究这些不稳定性的各个方面与包括Tokamaks（Tokamaks）的一系列应用相关的不同方面。在这些环形设备中，希望等离子体可以达到融合条件，用于驱动电流的射频的方案会产生具有较高速度和能量的重要电子种群。这些人群的稳定性及其如何响应不稳定性的发展需要理解。在涉及激光压缩靶标的融合方案中，快速电子进入目标的中央区域非常重要，并且对其行为的理解主要基于计算机模拟。在我们的大规模实验中，模拟结果与现实之间的关系将更容易看到。高功率RF辐射的产生范围从雷达到医疗，其应用很大程度上取决于高功率电子束的不稳定性以及其能量转化为电磁波。我们的工作应该对这些过程中的某些过程有增强的了解，特别是对来自意想不到的不稳定性的寄生辐射的产生。最后，高能量颗粒的光束在空间和天体物理等离子体中非常普遍，从地球的磁层到脉冲星和伽马射线玻璃剂。从这项研究中得出的不稳定性的基本物理学的理解将使人们对将理论和数值技术应用于其他实际等离子体环境，包括融合实验。该项目将一个在实验束等离子体系统中具有丰富专业知识的团队汇集在一起​​，以及在理论和计算上的广泛体验，以及用于磁性的等离子体质量的plasma，Lassma prods plassmame plasma plasma prodmame prodmame prodmame prodmame prodmame prodma and Comparational Modegational模型。该实验旨在研究广泛的条件，并隔离对磁性和惯性融合方案和高功率辐射产生直接重要性的特定不稳定性。

项目成果

A robust plasma-based laser amplifier via stimulated Brillouin scattering

通过受激布里渊散射实现强大的基于等离子体的激光放大器

• DOI: 10.48550/arxiv.1311.2034
• 发表时间: 2013
• 作者: Alves P

Time-resolved turbulent dynamo in a laser plasma

• DOI: 10.1073/pnas.2015729118
• 发表时间: 2021-03-16
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Bott, Archie F. A.;Tzeferacos, Petros;Gregori, Gianluca
• 通讯作者: Gregori, Gianluca

Laboratory astrophysics: Investigation of planetary and astrophysical maser emission

• DOI: 10.1007/s11214-013-9963-z
• 发表时间: 2013-03
• 期刊: Space Science Reviews
• 影响因子: 10.3
• 作者: R. Bingham;R. Bingham;D. Speirs;B. Kellett;I. Vorgul;S. McConville;R. A. Cairns;A. Cross

Cyclotron maser radiation from inhomogeneous plasmas

• DOI: 10.1063/1.3551697
• 发表时间: 2011-02
• 期刊: Physics of Plasmas
• 影响因子: 2.2
• 作者: R. A. Cairns;I. Vorgul;R. Bingham;K. Ronald;D. Speirs;S. McConville;K. Gillespie;R. Bryson;A. Phelps;B. Kellett;A. Cross;C. Roberston;C. Whyte;Wenlong He

Apparatus for investigating non-linear microwave interactions in magnetised plasma

研究磁化等离子体中非线性微波相互作用的装置

• 发表时间: 2018
• 作者: K. Ronald