Radiative cooling instabilities in magnetized high-density plasmas.

该学生将参与帝国理工学院MAGPIE脉冲功率设施的实验研究，研究高能密度等离子体物理，并应用于实验室天体物理学。这个博士项目将专注于由X射线驱动的目标烧蚀产生的逆流等离子体的相互作用。在这些等离子体碰撞时形成的致密和磁化的等离子体受到各种辐射不稳定性的发展，例如非线性薄壳不稳定性和场冷却不稳定性，这些不稳定性在许多天体物理系统和惯性约束聚变（ICF）中很常见。实验将使用我们最近开发的实验平台进行，该实验平台利用线阵列z箍缩内爆产生的X射线，在箍缩的10-50 T磁场中形成等离子体（Halliday等人，Physics of Plasmas，29，042107（2022））。靶材料（碳、Si和高Z金属）的变化将允许等离子体流和所形成的停滞层的辐射冷却的强度的可控变化。烧蚀目标结构的变化还将允许控制所施加的扰动的波长和幅度，这将引发不稳定性并可能转变为湍流。在这些实验中将使用广泛的诊断方法，包括激光干涉成像法、法拉第旋转偏振法、汤姆逊散射法以及光学和X射线光谱法。实验数据将与数值模拟进行比较，并将为ICF和天体物理计算机代码的验证提供定量数据。

The student will be involved in experimental research at the MAGPIE pulsed power facility at Imperial College into physics of high energy density plasmas, with applications to Laboratory Astrophysics. This PhD project will focus on interactions of counter-streaming plasmas generated by x-ray driven ablation of targets. The dense and magnetised plasma formed at the collision of these plasmas is subject to the development of various radiative instabilities, such as nonlinear thin shell instability and Field's cooling instability, which are common in many astrophysical systems and in Inertial Confinement Fusion (ICF). Experiments will be performed using a recently developed by us experimental platform utilizing X-rays generated by wire array z-pinch implosions, with the plasma formed in a 10-50 T magnetic field of the pinch (Halliday et al, Physics of Plasmas, 29, 042107 (2022)). Variation of the target materials (Carbon, Si and high -Z metals) will allow controllable variation of the strength of the radiative cooling of the plasma flows and of the formed stagnation layer. Variations of the ablated target structure will also allow controlling wavelengths and amplitudes of the imposed perturbations, which will be initiating the instabilities and possibly transition to turbulence. A broad range of diagnostics will be used in these experiments, including laser interferometry imaging, Faraday rotation polarimetry, Thomson scattering and optical and x-ray spectroscopy. Experimental data will be compared with numerical simulations and will provide quantitative data for validation of ICF and Astrophysical computer codes.