High Resolution Dielectronic Recombination Studies at CRYRING
1998 (English)Doctoral thesis, comprehensive summary (Other academic)
The works presented in this thesis are based on experimental studies on dielectronic recombination (DR) at the Stockholm storage ring CRYRING. The experiments have taken full advantage of the low energy spread of the electron beam provided by the electron cooler of the ring. Energy resolution of 10-1eV at full width half maximum has been achieved. The high resolution combined with the techniques we developed for corrections of ion energy variations due to drag forces and for absolute energy calibration have enabled DR resonances to be determined with energy accuracy of ~10 meV. With achieved resolution and accuracy, the experimental data of lithium-like argon and neon provided strict tests of advanced atomic calculations. Comparison shows that high order correlation, relativistic and QED effects are needed for a correct description of the doubly excited states. In the case of boron-like argon, a complicated DR resonant structure has been observed with the achieved high resolution. DR resonances were also observed in the energy region below 0.01 eV, which indicates that possible DR resonances at even lower energy may dominate the recombination rate and account for the large rate enhancement found for some non-bare ions. Comparisons with the data show that calculations need to be improved further to reach a reasonable agreement.
The effect of external electric field on DR rates has been studied with Si11+ at 9 different well defined field strengths. Reasonable agreement with present theory is found for the magnitude of the rate enhancement. However, the enhancement as a function of electric field shows a different behavior as compared to the calculation. Further investigations are needed to clarify this puzzling discrepancy.
Place, publisher, year, edition, pages
Stockholm: Stockholm University , 1998. , 65 p.
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-62234ISBN: 91-7153-737-6OAI: oai:DiVA.org:su-62234DiVA: diva2:440612
Crothers, Donald M, Professor
Härtill 9 uppsatser2011-09-132011-09-132011-09-13Bibliographically approved