An investigation into low temperature dielectronic recombination rate coefficients

In both astrophysical and laboratory plasmas, understanding the charge state balance of an element is key in interpreting the spectral emission. One of the dominant recombination mechanisms in both types of plasmas is dielectronic recombination (DR). For astrophysical photoionized plasmas, low electron temperature DR rate coefficients are critically important in the ionization balance and are known to have large uncertainties in their calculated values. In this work, we seek to address this problem of accurate low temperature DR. Current theoretical methods are known to have large uncertainties in the low temperature regime due to uncertainties in calculating low-n doubly excited states. This can be seen from differences with storage ring measurements. Large configuration-interaction atomic structure calculations and the R-matrix approaches are both candidates for producing a more accurate atomic structure. We explore the use of large CI AUTOSTRUCTURE calculations to improve the low temperature DR rate coefficients, comparing with existing storage ring measurements. This work is in collaboration with new measurements being performed at the heavy ion storage ring CRYRING@ESR at the FAIR facility in Darmstadt, Germany