Strong field effects on structure and collisions of high-Z ions

In high-Z ions the innermost electrons are exposed to extremely strong electromagnetic fields. Therefore, in collisions of very heavy few-electron systems, like highly charged U-ions, relativistic and quantum electrodynamic (QED) effects can be probed very effectively. A concise review of the recent experimental achievements in this area will be presented. In particular, the actually obtained accuracy of the QED tests in strong fields will be discussed. Special emphasis will be given to radiative electron capture (REC), the time reversed approach of photoionization. Here, angular distribution of REC photons sensitively proves the rigorous relativistic treatment of the process, even at relatively low ion velocities. (C) 2003 Elsevier Science B.V. All rights reserved.