Experimental evidence for magnetic field effects on dielectronic recombination via high Rydberg states

We report the first experimental observation of magnetic field effects on d ielectronic recombination (DR) via highly excited Rydberg levels. Crossed s tatic electric and magnetic fields E-y and B-z were imposed on the collisio n region in high resolution DR measurements with Li-like Cl14+ ions at the heavy ion storage ring TSR in Heidelberg. Enhancement of DR rate coefficien ts ct for the group of high Rydberg states attached to the 2P(1/2) and 2P(3 /2) series limits was observed when motional electric fields E-y up to 380 V/cm were introduced. The associated enhancement rate d alpha/dE(y) which w e found to be constant at least for E-y less than or equal to 100 V/cm decr eased by almost a factor of 2 when the longitudinal field B-z was increased from 20 to 69 mT.