Non-linear FEL science

After a brief introduction to X-ray-induced processes, results from some of the first experiments carried at X-ray free-electron lasers will be presented and compared with theory . It will be shown that the X-rays from an X-ray free-electron laser are so intense that (a) an atom can be completely stripped of all its electrons; (b) inner-shell ionization can be as fast as the Auger decay of an inner-shell hole, thus leading to the efficient formation of double-core-hole states; and (c) the characteristics of the Auger decay process itself can be modified.