FIELD-ENHANCED RADIATIVE RECOMBINATION AT LOW ENERGIES

The effect of external time-dependent electric fields (TDF) on the rad iative recombination (RR) process near the zero energy threshold and f or capture to high Rydberg states is examined in detail. The momentum coherence phenomenon discovered recently causes a large enhancement in the cross section, with the maximum located near the principal quantu m number n(g) congruent-to Z/g, where Z is an effective charge of the ion and g is the field momentum defined by the time integral of the el ectric field perturbation. The sensitivity of the RR cross sections on TDF may be used to study the field conditions in the interaction regi on where the recombination reaction takes place. Dependence of the enh ancement on field parameters is presented in a form suitable for data analyses. Calculated cross sections are compared with recent experimen ts on Ar15+ and U28+, Au25+ and on ions with Z < 25, where sizable enh ancements were observed.