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

9412916 Rocca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。我们建议进行国际合作，将实验和理论结合起来，研究由快速毛细管放电产生的热等离子体通道，以开发有效的相干和非相干软x射线辐射源。科罗拉多州立大学最近进行的实验结果证实，毛细管通道的电流上升时间约为10ns，非常快的激发可以产生直径小的致密等离子体柱，电子温度为几百eV，使用的电流比在太瓦脉冲功率机器中获得热等离子体的电流小一个数量级。结果包括在低至40kA的电流下，在直径为1.5 -2.5mm的毛细血管中观察到p3 -3s激光候选跃迁中氖样钙的发射。这种通过直接放电激发有效产生小直径（200um）等离子体柱的能力，为实现紧凑、高效的软x射线激光器提供了一条新的途径。此外，将电储存的能量直接转移到可再生的小直径热毛细管等离子体中，可以产生低成本的非相干x射线源。拟议的合作研究将结合科罗拉多州立大学进行的毛细管放电实验和毛细管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磁流体动力学和辐射输运代码。在新的快速放电制度下，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/原子物理计算相比较，有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.