Photoexcitation and photoionization spectroscopy of very highly charged ions

在接下来的几年里，一些新的自由电子激光（FEL）设备将会投入使用。在设想的高光子能量下的高通量辐射下，将有可能对光子与稀有、低密度目标物种（如高电荷离子）相互作用进行高分辨率实验。通过将超亮FEL辐射与电子束离子阱（EBIT）相结合，可以用少量电子系统研究到类锂U89+离子的光子-离子相互作用。用荧光光谱和离子态光谱的方法研究光激发和光电离，不仅将为天文学和等离子体物理学的应用提供数据，而且为精确测量基础物理理论，特别是强电磁场中的量子电动力学的有效性提供独特的可能性。此外，多光子过程可以在高能光子状态下进行研究，这是迄今为止尚未实现的。因此，关于光与物质相互作用的基本的、新的见解将通过提出的实验得以实现。

In the next several years a number of new free-electron-laser (FEL) facilities will become available. With the envisaged high flux radiation at high photon energies access to high-resolution experiments on the interaction of photons with rare, low-density target species, such as very highly charged ions, will become possible. By the combination of super brilliant FEL radiation with an electron-beam-ion-trap (EBIT) photon-ion interactions can be studied with few-electron systems up to lithiumlike U89+ ions. Photoexcitation and photoionization studied with the methods of fluorescence spectroscopy and ioncharge-state spectroscopy will provide not only data for applications in astro and plasma physics but also open unique possibilities for precision measurements testing the validity of fundamental physics theories, especially of quantum electrodynamics in strong electromagnetic fields. Moreover, multiphoton processes can be investigated in a regime of high-energy photons that has not been accessible so far. Thus, fundamental, new insights about the interaction of light with matter will become accessible by the proposed experiments.