International Collaboration for the Study of Fast Capillary Discharge Plasmas as Efficient Sources for X-Ray Radiation

9412916重要的现有和新兴应用需要开发高效和紧凑的X射线辐射源。我们建议开展一项国际合作，将实验和理论工作结合起来，研究由快速毛细放电产生的热等离子体通道，以开发高效的相干和非相干软X射线辐射源。这项拟议的研究是由科罗拉多州立大学最近进行的实验结果推动的，这些实验证实，以非常快的速度激励电流上升时间约为10 ns的毛细管通道，可以利用比在太瓦脉冲功率机器中获得热等离子体所用的电流小一个数量级以上的电流，产生直径较小、电子温度为数百eV的致密等离子体柱。结果包括在低至40kA的电流下观察到了直径1.5-2.5 mm的毛细管中3P-3S激光候选类霓虹钙跃迁的发射。这种通过直接放电激励产生小直径(200um)等离子体柱的能力可以为实现紧凑和高效的软X射线激光提供一条新的途径。此外，将电存储的能量直接转移到可重复使用的小直径热毛细等离子体中，可产生具有成本效益的非相干X射线源。拟议的合作研究将结合在科罗拉多州立大学进行的毛细放电实验和对毛细放电等离子体辐射特性的详细理论分析，这将基于列别捷夫物理研究所开发的详细的磁流体动力学和辐射输运代码。将工作在新的快放电状态下的毛细管等离子体的空间和时间分辨软X射线光谱与最先进的MHD/原子物理计算进行比较，可望提供对这些等离子体的更多了解，并为它们发展成为有效的相干和非相干软X射线辐射源提供必要的指导。

9412916 Rocca Important existing and emerging applications require the development of efficient and compact sources of x-ray radiation. We propose an international collaboration to combine experimental and theoretical efforts in the study of the hot plasma channels produced by fast capillary discharges for the development of efficient sources of both coherent and incoherent soft x-ray radiation. The proposed research is motivated by results of recent experiments conducted at Colorado State University, that confirm that very fast excitation of capillary channels with current risetimes of approximately 10ns can generate dense plasma columns of small diameter with electron temperatures of a few hundred eV utilizing currents that are more than an order of magnitude smaller than those employed to obtain hot plasmas in Terawatt pulse power machines. Results include the observation of emission from the 3p-3s laser candidate transitions of neon-like calcium in 1.5 -2.5mm diameter capillaries at currents as low as 40kA. Such capability for efficiently generating plasma columns of small (200um) diameter by direct discharge excitation could provide a new route towards compact and efficient soft x-ray lasers. Also, the direct transfer of electrically stored energy into reproducible hot capillary plasmas of small diameter and could result in a cost efficient incoherent x-ray source. The proposed cooperative research will combine capillary discharge experiments conducted at Colorado State University with a detailed theoretical analysis of the radiative properties of capillary discharge plasmas, which will be based on elaborate magnetohydrodynamic and radiation transport codes developed at the Lebedev Physics Institute. The comparison of spatially and time resolved soft x-ray spectra from capillary plasmas operating in a new fast discharge regime with state of the art MHD/atomic physics calculations is expected to provide an increased understanding of these plasmas and the necessary guidance for their development into efficient practical sources of coherent and incoherent soft x-ray radiation.