Electron‐ion recombination in merged beams

Detailed studies of recombination processes between electrons and highly charged ions have become possible by recent improvements of merged‐beams experiments. We discuss in particular measurements with stored cooled ion beams at the Test Storage Ring (TSR) in Heidelberg. The cross section of dielectronic recombination was measured with high energy resolution for few‐electron systems up to the nuclear charge of Cu at a relative energy up to 2.6 keV. At low energy (≊0.1 eV) total recombination rates of several ions were measured and compared with calculated radiative recombination rates. Laser‐stimulated recombination of protons and of C6+ ions was investigated as a function of the photon energy using visible radiation. Both the total recombination rates and the stimulated recombination spectra indicate that in spite of the short interaction time in merged beams, also collisional capture of electrons into weakly bound levels (related to three‐body recombination) could be important.