Enhanced dielectronic recombination of lithium-like Ti^{19+} ions in external $\bi{E}\times\bi{B}$ fields

Dielectronic recombination(DR) of lithium-like Ti^{19+}(1s^2 2s) ions via $2s\to 2p$ core excitations has been measured at the Heidelberg heavy ion storage ring TSR. We find that not only external electric fields ($0 \leq E_y \leq 280$ V/cm) but also crossed magnetic fields (30 mT$ \leq B_z \leq$ 80mT) influence the DR via high-n $2p_jn\ell$-Rydberg resonances. This result confirms our previous finding for isoelectronic Cl^{14+} ions [Bartsch T {\it et al}, \PRL {\bf 82}, 3779 (1999)] that experimentally established the sensitivity of DR to $\bi{E}\times\bi{B}$ fields. In the present investigation the larger 2p_{1/2}-2p_{3/2} fine structure splitting of Ti^{19+} allowed us to study separately the influence of external fields via the two series of Rydberg DR resonances attached to the 2s -> 2p_{1/2} and 2s -> 2p_{3/2} excitations of the Li-like core, extracting initial slopes and saturation fields of the enhancement. We find that for $E_y \gtrsim 80$ V/cm the field induced enhancement is about 1.8 times stronger for the 2p_{3/2} series than for the 2p_{1/2} series.