FIELD ENHANCED DIELECTRONIC RECOMBINATION OF SI11+ IONS

The enhancement of dielectronic recombination by applied electric fiel ds has been observed and measured for the first time in a wide range o f controlled and measurable fields using multiply charged ions. The he avy ion storage ring CRYRING at Stockholm University was used to store a beam of Si11+ and collide it with a cold electron target. Rydberg r esonances up to n = 25 are resolved for both the 2(p3/2) and 2(p1/2) s eries. The observation of a substantial monotonic increase of the rate coefficient for the group of higher Rydberg states is in puzzling dis agreement with theoretical calculations of electric field enhanced die lectronic recombination.