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UK APAP Network

英国APAP网络

基本信息

批准号：
PP/E001254/1
负责人：
Nigel Badnell
金额：
$ 41.04万
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：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=PP%2FE001254%2F1
关键词：
UK APAP Network

项目摘要

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.

等离子体遍布我们的宇宙，存在于恒星大气层、星系中的星际气体云、行星状星云、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出丰富的信息，特别是在等离子体中存在的离子发射的光谱线中。近年来，从Chandra、XMM-Newton、HST、FUSE、SOHO等任务中获得了大量的XUV光谱数据。每个物体的物质状态--温度和密度的分布，化学成分，流速--可以通过光谱数据的诊断分析来确定，其中模型，结合了物体的全部物理特性，面对观察。这些信息对于我们理解宇宙的起源和演化至关重要。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重要的作用，因此需要精确的原子数据。这可能令人惊讶，但离子产生的光谱中有很大一部分尚未探索。观测和理论之间的巨大差异也仍然存在。例如，在H II区和行星状星云中，导出的元素丰度存在数量级异常。在活动星系核（AGN）的X射线谱中也存在观测与理论的不匹配。我们打算进行新的计算的电子-离子复合速率系数，以解决这些差异。近年来，我们已经表明，需要进行精确的R-矩阵计算的电子-离子碰撞的个别离子，以解决大，长期存在的差异之间的观测和计算线强度碰撞（天体物理和实验室）等离子体。我们建议将这些计算扩展到从H-样到Na-样的所有isolectronic序列，为所有重要离子提供全面而准确的数据集。需要对理论数据进行评估，特别是根据天体物理学和实验室测量进行基准测试，以便确定谱线，并提供准确的波长和不确定性估计。我们打算通过建立一个基于网络的档案库，向更广泛的用户社区提供所有这些基本数据和派生数据，该档案库将包含通过物理建模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。通过这一提议，我们的目标是加强实验，观测和理论研究之间的合作。