权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Hybrid simulations of weakly collisional/collisionless shocks in laser produced plasmas

激光产生等离子体中弱碰撞/无碰撞冲击的混合模拟

基本信息

批准号：
EP/N002644/1
负责人：
Brian Reville
金额：
$ 12.56万
依托单位：
Queen's University Belfast
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FN002644%2F1
关键词：
Hybrid simulations weakly collisional collisionless

项目摘要

Plasma shocks play an important role in a number of situations, ranging from exploding stars to laser driven fusion experiments. Recent advances in experimental capabilities have inspired efforts to connect shocks produced in the laboratory with their astrophysical counterparts. This is a rapidly developing research area generating new collaborations between the laboratory plasma physics and astrophysics communities. Establishing and isolating clear and distinguishable physical effects that should occur in both systems is the primary goal. These can then be used to make physically meaningful connections between processes occurring on vastly different scales. Numerical simulations are a powerful aid in this effort. This proposal concerns the construction a novel hybrid plasma simulation code, that will explore the physics of shock waves in plasmas with arbitrary levels of collisionality, with a particular emphasis on systems in the transitional regime, moving between weakly collisional to collisionless plasmas.In most astrophysical systems in which shock-waves are observed to occur, the Coulomb mean free path is considerably larger than the macroscopic scales of interest. Thus, the abrupt transition in the fluid properties (density, temperature, etc.), must be mediated by collisionless effects, i.e. through the collective interaction between charged particles and electromagnetic fields. This is a fascinating area of physics, whereby collective processes occurring on microscopic scales have a dramatic effect on the macroscopic behaviour. In astrophysics, understanding the kinetics of such shocks is of enormous significance, since the radiation from the thermal and non-thermal particles produced by the shock provide us with vital information about the Universe. While collisionless shocks are the norm in astrophysics, in terrestrial experiments, reproducing the necessary plasma conditions to ensure Coulomb collisions are negligible is challenging. Experiments using the world's largest laser at the National Ignition Facility (NIF), Livermore, can provide the necessary conditions, but access to this facility is limited. However, numerical investigations can be used to identify common features of shocks at different levels of collisonality, opening the possibility of investigating collisionless shock physics at more modest laser energies. This would allow more in depth investigations of astrophysically relevant shock physics to be carried out, using facilities such as the Vulcan laser at Rutherford Appleton Laboratories. Preliminary results from a recent experiment on Vulcan indicate that this is indeed possible.We will develop a new numerical tool to facilitate such investigations. The code is based on the KALOS formalism (Bell et al., 2006, PPCF), where collisions are accurately modelled using a Fokker-Planck description. A novel hybrid plasma scheme, using a Vlasov-Fokker-Planck treatment of the ions will be developed, capable of investigating shocks in plasmas with arbitrary levels of collisionality. We anticipate this will improve our predictive capability, providing further insight into the physics of collisionless shocks. The results will be of interest to both the astrophysics and the laser plasma communities. The code will also have further applications in both fields.

从恒星爆炸到激光驱动的聚变实验，等离子体冲击在许多情况下都发挥着重要作用。最近在实验能力方面的进展促使人们努力将实验室产生的电击与它们的天体物理对应物联系起来。这是一个快速发展的研究领域，在实验室等离子体物理学和天体物理学社区之间产生了新的合作。建立和隔离两个系统中应该发生的明确和可区分的物理影响是主要目标。然后，这些可以用来在非常不同规模的过程之间建立物理上有意义的联系。在这方面，数值模拟是一种强有力的帮助。这项建议涉及建立一个新的混合等离子体模拟程序，该程序将探索具有任意碰撞水平的等离子体中的冲击波的物理，特别强调处于过渡区域的系统，在弱碰撞到无碰撞的等离子体之间移动。在大多数观察到发生激波的天体物理系统中，库仑平均自由程远远大于所关注的宏观尺度。因此，流体性质(密度、温度等)的突然转变必须通过无碰撞效应来调节，即通过带电粒子和电磁场之间的集体相互作用。这是一个令人着迷的物理学领域，微观尺度上发生的集体过程对宏观行为产生了戏剧性的影响。在天体物理学中，了解这种激波的动力学具有巨大的意义，因为激波产生的热和非热粒子的辐射为我们提供了关于宇宙的重要信息。虽然无碰撞冲击在天体物理学中是常态，但在地面实验中，重现必要的等离子体条件以确保库仑碰撞是可以忽略的，这是具有挑战性的。利弗莫尔国家点火设施(NIF)使用世界上最大的激光进行的实验可以提供必要的条件，但进入该设施的途径是有限的。然而，数值研究可以用来确定不同共振性水平上的激波的共同特征，从而打开了在更适中的激光能量下研究无碰撞激波物理的可能性。这将允许利用卢瑟福·阿普尔顿实验室的瓦肯激光器等设施，对与天体物理相关的冲击物理进行更深入的研究。最近在火神上进行的一项实验的初步结果表明，这确实是可能的。我们将开发一种新的数值工具来促进这类研究。该代码基于Kalos形式主义(Bell等人，2006，PPCF)，其中碰撞使用福克-普朗克描述进行精确建模。将开发一种新的混合等离子体方案，使用Vlasov-Fokker-Planck处理离子，能够研究具有任意碰撞水平的等离子体中的冲击。我们预计这将提高我们的预测能力，为无碰撞冲击的物理学提供进一步的洞察。这一结果将对天体物理学和激光等离子体领域都很有意义。该代码还将在这两个领域得到进一步的应用。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Electron acceleration by wave turbulence in a magnetized plasma

DOI：
10.1038/s41567-018-0059-2
发表时间：
2018-03
期刊：
Nature Physics
影响因子：
19.6
作者：
A. Rigby;F. Cruz;B. Albertazzi;R. Bamford;A. Bell;J. Cross;F. Fraschetti;P. Graham;Y. Hara;P. Kozlowski;Y. Kuramitsu;D. Lamb;S. Lebedev;J. Marquès;F. Miniati;T. Morita;M. Oliver;B. Reville;Y. Sakawa;Sreyash Sarkar;C. Spindloe;R. Trines;P. Tzeferacos;L. Silva;R. Bingham;M. Koenig;G. Gregori
通讯作者：
A. Rigby;F. Cruz;B. Albertazzi;R. Bamford;A. Bell;J. Cross;F. Fraschetti;P. Graham;Y. Hara;P. Kozlowski;Y. Kuramitsu;D. Lamb;S. Lebedev;J. Marquès;F. Miniati;T. Morita;M. Oliver;B. Reville;Y. Sakawa;Sreyash Sarkar;C. Spindloe;R. Trines;P. Tzeferacos;L. Silva;R. Bingham;M. Koenig;G. Gregori

Evolution of the Design and Fabrication of Astrophysics Targets for Turbulent Dynamo (TDYNO) Experiments on OMEGA

OMEGA 湍流发电机 (TDYNO) 实验天体物理目标设计和制造的演变