Experimental Evidence for Magnetic Field Effects on Dielectronic Recombination via High Rydberg States

We report the first experimental observation of magnetic field effects on dielectronic recombination (DR) via highly excited Rydberg levels. Crossed static electric and magnetic fields E{sub y} and B{sub z} were imposed on the collision region in high resolution DR measurements with Li-like Cl{sup 14+} ions at the heavy ion storage ring TSR in Heidelberg. Enhancement of DR rate coefficients {alpha} for the group of high Rydberg states attached to the 2p{sub 1/2} and 2p{sub 3/2} series limits was observed when motional electric fields E{sub y} up to 380thinspthinspV/cm were introduced. The associated enhancement rate d{alpha}/dE{sub y} which we found to be constant at least for E{sub y}{le}100 V/cm decreased by almost a factor of 2 when the longitudinal field B{sub z} was increased from 20 to 69thinspthinspmT. {copyright} {ital 1999} {ital The American Physical Society}