UK APAP Network

等离子体弥漫着我们的宇宙，存在于恒星大气、星系中的星际气体云、行星星云、超新星遗迹、黑洞吸积盘等等。所有这些物体的光谱学都显示了丰富的信息，特别是在等离子体中存在的离子发射的谱线中。近年来，从钱德拉、XMM-牛顿、HST、FUSE、SOHO等任务获得了大量的XUV光谱数据。每个物体中物质的状态-温度和密度的分布、化学成分、流动速度-可以通过对光谱数据的诊断分析来确定，在这些数据中，模型结合了物体的全部物理特性，与观测结果对峙。这些信息是我们理解宇宙起源和演化的基础。电子和光子与原子、离子和分子的碰撞在天体物理等离子体中起着基本的作用，因此有必要计算出准确的原子数据。这可能令人惊讶，但离子产生的光谱中有很大一部分仍未被探索。观测和理论之间的巨大差异也仍然存在。例如，H II区和行星状星云的元素丰度存在数量级的异常。在活动星系核(AGN)的X射线光谱中，也存在着观测与理论的不匹配。我们打算对电子-离子复合速率系数进行新的计算，以解决这些差异。近年来，我们已经证明了需要对单个离子的电子-离子碰撞进行精确的R矩阵计算，以解决碰撞(天体物理和实验室)等离子体中观测到的线强度和计算的线强度之间长期存在的巨大差异。我们建议将这些计算扩展到从类H到类Na的所有等电子序列，为所有重要离子提供一个全面和准确的数据集。理论数据需要根据天体物理和实验室测量进行评估和基准，特别是为了确定谱线，并提供准确的波长和不确定度估计。我们打算通过建立一个基于网络的档案向更广泛的用户群体提供所有这些基本的和衍生的数据，该档案将包含用物理模型解释天体物理和实验室等离子体光谱所需的所有原子数据。通过这一建议，我们旨在加强实验、观测和理论研究之间的合作。

Plasmas permeate our Universe, being present in stellar atmospheres, interstellar gas clouds in galaxies, planetary nebulae, supernova remnants, black hole accretion disks, and so on. Spectroscopy of all these objects has shown a richness of information, in particular in the spectral lines that are emitted by the ions that are present in the plasmas. In recent years, an overwhelming amount of XUV spectroscopic data have been obtained from missions such as Chandra, XMM-Newton, HST, FUSE, SOHO. The state of matter in each object --- the distribution of temperature and density, chemical composition, flow velocities --- can be determined through diagnostic analysis of spectral data in which models, incorporating the full physics of the object, confront the observations. This information is fundamental for our understanding of the origin and evolution of the Universe. Collisions of electrons and photons with atoms, ions and molecules play a fundamental role in astrophysical plasmas, and it is therefore necessary that accurate atomic data are calculated. It might be surprising, but a large fraction of the spectra produced by ions is still unexplored. Large discrepancies between observations and theory are also still present. For example, there are order-of-magnitude anomalies in the derived elemental abundances in H II regions and Planetary Nebulae. A mis-match between observation and theory is also present in the X-ray spectra of Active Galactic Nuclei (AGN). We intend to perform new calculations of electron-ion recombination rate coefficients to address these discrepancies. In recent years, we have shown the need to perform accurate R-matrix calculations of electron-ion collisions for individual ions, in order to solve the large, long-standing discrepancies between observed and calculated line intensities in collisional (astrophysical and laboratory) plasmas. We propose extending these calculations to all isolectronic sequences from H-like up to Na-like, providing a comprehensive and accurate dataset for all important ions. The theoretical data need to be assessed and benchmarked against astrophysical and laboratory measurements, in particular, in order to identify spectral lines and to provide accurate wavelengths and uncertainty estimates. We intend to provide all of these fundamental and derived data to the wider user community by setting up a web-based archive which will contain all of the atomic data needed to interpret, with physical modelling, the spectra of astrophysical and laboratory plasmas. With this proposal, we aim to strengthen the collaboration between experimental, observational and theoretical research.