Electronic and photonic interactions involving highly charged tungsten ions

电离和复合决定了等离子体中的离子电荷状态分布，从而决定了等离子体的电磁辐射发射。此外，原子结构和激发离子的衰变过程的数据需要等离子体诊断和建模。现有的等离子体相关的数据库与低和中等原子序数Z的元素是相对可靠的，但是，有较大的不确定性较重的多电子离子，甚至最基本的原子过程还没有得到充分的理解。鉴于钨在聚变等离子体中的关键重要性，因此建议利用最先进的实验技术来研究钨离子的电子碰撞电离和复合以及光激发，钨离子代表更一般的多电子原子，在广泛的电荷状态和电子和光子能量范围内，目前可用的最佳能量分辨率。我们的研究小组和我们的合作者在应用碰撞束技术研究方面的独特专业知识将被利用来帮助解决在实验室和天体物理等离子体环境中模拟高Z原子行为的突出问题。与此同时，使用钨在不同的电荷状态下，一组模型的多电子原子的物理将被解决，旨在了解未探索的现象，如广泛的强共振的主导地位，偶尔被观察到发生在复杂的重原子的碰撞。电子和光子将被用作最好的探针来阐明这些尚未被系统研究的现象。

Ionization and recombination determine the ion charge state distribution in a plasma and hence the emission of electromagnetic radiation from the plasma. In addition, data on atomic structure and decay processes of excited ions are needed for plasma diagnostics and modeling. Available plasma-related data bases for elements with low and intermediate atomic number Z are relatively reliable, however, there are large uncertainties for heavier multi-electron ions, where even the most fundamental atomic processes are not yet sufficiently well understood. In view of the critical importance of tungsten in fusion plasmas it is therefore proposed to make use of the most advanced experimental techniques to study electron-impact ionization and recombination as well as photo-excitation of tungsten ions, representing the more general class of multi-electron atoms, in a wide range of charge states and of electron and photon energies at the best possible energy resolution presently available. The unique expertise of our research group and our collaborators in research applying colliding beams techniques will be exploited to help resolve outstanding problems in modeling the behavior of high-Z atoms in laboratory-based as well as in astrophysical plasma environments. At the same time, using tungsten in different charge states, the physics of a model set of many-electron atoms will be addressed aiming at the understanding of unexplored phenomena, such as the dominance of broad strong resonances, that have occasionally been observed to occur in collisions of complex heavy atoms. Electrons and photons will be used as the finest available probes to elucidate these phenomena that have not yet been systematically studied.