Ion acceleration via plasma turbulence and collisionless shock generation

通过等离子体湍流和无碰撞冲击产生进行离子加速

• 批准号: 2465175
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2465175
• 关键词: Ion; acceleration; via; plasma; turbulence

High-power laser facilities have made unprecedented progress in recent years. With this the laser-matter interaction has entered parameter regimes of interest for laboratory astrophysics. In particular, the interactions of relativistic short intense lasers with matter can generate some high energy density states (HEDS). For example, magnetic turbulent plasmas can be formed while laser produced high current electron beams transport in solid targets via Weibel instability, and high-energy high-current electron and ion beams can be produced while intense laser pulses interact with gas or solid density plasmas. This instability is widely thought to underpin the physics of relativistic outflows in astrophysical objects (e.g., gamma-ray bursts, pulsar winds, active galactic nuclei), especially as the source of the collisionless shock waves responsible for generating nonthermal high-energy particles and radiations. High-power laser plasma experiments can produce unique parameter regimes with high energy density, while numerical simulations can provide a great variety of information of complex and dynamic systems with high performance computers, which may be measured in experiments. In this project, Weibel-type magnetic turbulence will be modelled by intense laser solid interactions. Previous simulations have been carried out with low spatial resolutions, limited time and limited to 2D geometry, which cannot be compared directly to experimental observation. With our new code, magnetic plasma turbulence will modelled more accurately in 3D, so that direct comparison with experiments could be made. We shall focus on the micro-processes, like Weibel instabilities and two stream instabilities between forward currents of relativistic hot electrons and cold return currents of background electrons under the irradiance of laser pulses under different intensities, and the subsequent development of magnetic turbulence over the time scale of a few tens of picosecond. The temporal evolution and spatial profiles (power law of k spectra) of magnetic fields will be obtained by kinetic PIC simulations.

近年来，高功率激光装置取得了前所未有的进展。有了这个激光物质相互作用已进入参数的实验室天体物理学的利益制度。特别是，相对论短强激光与物质相互作用可以产生一些高能密度态（HEDS）。例如，当激光产生的强电流电子束通过韦伯不稳定性在固体靶中传输时，可以形成磁性湍流等离子体，并且当强激光脉冲与气体或固体密度等离子体相互作用时，可以产生高能强电流电子和离子束。这种不稳定性被广泛认为是天体物理学对象中相对论性流出的物理基础（例如，伽马射线爆发、脉冲星风、活动星系核），特别是作为产生非热高能粒子和辐射的无碰撞冲击波的来源。高功率激光等离子体实验可以产生独特的高能量密度的参数区域，而数值模拟可以提供复杂和动态系统的各种信息，这些信息可以在实验中测量。在这个项目中，韦伯型磁湍流将模拟强激光固体相互作用。以前的模拟已经进行了低空间分辨率，有限的时间和有限的二维几何形状，这不能直接与实验观察。通过我们的新代码，磁等离子体湍流将在3D中更准确地建模，以便可以与实验进行直接比较。我们将着重讨论在不同强度的激光脉冲辐照下，相对论热电子的前向流和背景电子的冷返回流之间的微过程，如韦伯不稳定性和双流不稳定性，以及随后在几十皮秒时间尺度上磁湍流的发展。将通过动力学PIC模拟获得磁场的时间演化和空间分布（k谱的幂律）。