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Department of Applied Mathematics and Theoretical Physics



  • 2017-date: PhD student, University of Cambridge
  • 1995-2017: Troubleshooting accountant, finance manager
  • 1994-1995: MASt in Mathematics (Part III Maths), University of Cambridge
  • 1991-1994: BSc Physics, University of Leeds


Roger is a member of the Department of Applied Mathematics and Theoretical Physics atomic astrophysics research group. His current research interests are focussed on imporving modelling of atomic processes in plasma. The improvements lead to better diagnosis of various properties of the plasma, such as temperature, density and chemical abundance. The current focus is improving the modelling normally used in the solar corona to better diagnose ions formed lower down in the solar atmosphere, in the transition region and chromosphere. The initial aim has been to model the effect of higher densities on the ionisation and recombination processes involving free electrons which are already included in the coronal modelling. This has been developed further by adding other atomic processes not normally included in coronal modelling, such as those induced by the solar radiation and those which occur during collisions with atoms and ions. Test are currently being made as to how much the new modelling improves understanding of the plasma in the lower atmosphere.

Selected Publications

Lead author

  • Dufresne R. P., Del Zanna G., Storey P. J., Modelling low charge ions in the solar atmosphere, MNRAS (2021), submitted
  • Dufresne R. P., Del Zanna G., Badnell N. R., The influence of photo-induced processes and charge transfer on carbon and oxygen in the lower solar atmosphere, MNRAS (2021), in press
  • Dufresne R. P., Del Zanna G., Badnell N. R., The effects of density on the oxygen ionisation equilibrium in collisional plasmas, MNRAS (2020), 497, 1443
  • Dufresne R. P., Del Zanna G., Modelling ion populations in astrophysical plasmas: carbon in the solar transition region, A&A (2019), 626, A123


  • Temple M.J. et. al., Fe III emission in quasars: evidence for a dense turbulent medium, MNRAS (2020), 496, 2565

Research Groups

Astrophysical Fluid Dynamics
Atomic Astrophysics




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