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Radiative recombination of bare Bi83+: Experiment versus theory

A. Hoffknecht·C. Brandau·T. Bartsch·C. Boehme·H. Knopp·S. Schippers·A. Mueller·C. Kozhuharov·K. Beckert·F. Bosch·B. Franzke·A. Kraemer·P. H. Mokler·F. Nolden·M. Steck·Th. Stoehlker·Z. Stachura
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Abstract

Electron-ion recombination of completely stripped Bi83+ was investigated at the Experimental Storage Ring (ESR) of the GSI in Darmstadt. It was the first experiment of this kind with a bare ion heavier than argon. Absolute recombination rate coefficients have been measured for relative energies between ions and electrons from 0 up to about 125 eV. In the energy range from 15 meV to 125 eV a very good agreement is found between the experimental result and theory for radiative recombination (RR). However, below 15 meV the experimental rate increasingly exceeds the RR calculation and at Erel = 0 eV it is a factor of 5.2 above the expected value. For further investigation of this enhancement phenomenon the electron density in the interaction region was set to 1.6E6/cm3, 3.2E6/cm3 and 4.7E6/cm3. This variation had no significant influence on the recombination rate. An additional variation of the magnetic guiding field of the electrons from 70 mT to 150 mT in steps of 1 mT resulted in periodic oscillations of the rate which are accompanied by considerable changes of the transverse electron temperature.

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A. Hoffknecht, C. Brandau, T. Bartsch, C. Boehme, H. Knopp, S. Schippers, A. Mueller, C. Kozhuharov, K. Beckert, F. Bosch, B. Franzke, A. Kraemer, P. H. Mokler, F. Nolden, M. Steck, Th. Stoehlker, Z. Stachura. 2000-03-28. Radiative recombination of bare Bi83+: Experiment versus theory. https://doi.org/10.1103/physreva.63.012702

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