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Faculty of Mathematics

 

 

Career

  • 2023- : Post-doctoral research associate, DAMTP, University of Cambridge
  • 2022-2023: Visiting researcher (DAMTP) / research study administrator (Medical Genetics), University of Cambridge
  • 2017-2022: PhD student, DAMTP, University of Cambridge
  • 1995-2017: Troubleshooting accountant, finance manager
  • 1994-1995: Master of Advanced Study in Mathematics (Part III Maths), University of Cambridge
  • 1991-1994: BSc Physics, University of Leeds

Research

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.

Publications

New atomic data for C I Rydberg states compared with solar UV spectra
PJ Storey, RP Dufresne, G Del Zanna
– Monthly Notices of the Royal Astronomical Society
(2023)
stad2736
A benchmark study of atomic models for the transition region against quiet Sun observations
R Dufresne, GD Zanna, H Mason
(2023)
A benchmark study of atomic models for the transition region against quiet Sun observations
RP Dufresne, G Del Zanna, HE Mason
– Monthly Notices of the Royal Astronomical Society
(2023)
521,
4696
Path-lengths in the quiet Sun transition region using O iv lines from IRIS
YK Rao, G Del Zanna, HE Mason, R Dufresne
– Monthly Notices of the Royal Astronomical Society
(2022)
517,
1422
Modelling line emission in the lower solar atmosphere
R Dufresne
(2021)
Modelling low charge ions in the solar atmosphere
RP Dufresne, G Del Zanna, PJ Storey
– Monthly Notices of the Royal Astronomical Society
(2021)
505,
3968
The influence of photo-induced processes and charge transfer on carbon and oxygen in the lower solar atmosphere
RP Dufresne, G Del Zanna, NR Badnell
– Monthly Notices of the Royal Astronomical Society
(2021)
503,
1976
Effects of density on the oxygen ionization equilibrium in collisional plasmas
RP Dufresne, G Del Zanna, NR Badnell
– Monthly Notices of the Royal Astronomical Society
(2020)
497,
1443
Fe iii  emission in quasars: evidence for a dense turbulent medium
MJ Temple, GJ Ferland, AL Rankine, PC Hewett, NR Badnell, CP Ballance, G Del Zanna, RP Dufresne
– Monthly Notices of the Royal Astronomical Society
(2020)
496,
2565
Modelling ion populations in astrophysical plasmas: carbon in the solar transition region⋆
RP Dufresne, G Del Zanna
– Astronomy & Astrophysics
(2019)
626,
A123

Research Groups

Astrophysics
Atomic Astrophysics