UK APAP Network
Lead Research Organisation:
University of Strathclyde
Department Name: Physics
Abstract
Plasmas permeate our Universe, being present in stellar atmospheres, interstellar gas clouds in galaxies, planetary nebulae, supernova remnants, black hole accretion disks, and so on. Spectroscopy of all these objects has shown a richness of information, in particular in the spectral lines that are emitted by the ions that are present in the plasmas. In recent years, an overwhelming amount of XUV spectroscopic data have been obtained from missions such as Chandra, XMM-Newton, HST, FUSE, SOHO. The state of matter in each object --- the distribution of temperature and density, chemical composition, flow velocities --- can be determined through diagnostic analysis of spectral data in which models, incorporating the full physics of the object, confront the observations. This information is fundamental for our understanding of the origin and evolution of the Universe. Collisions of electrons and photons with atoms, ions and molecules play a fundamental role in astrophysical plasmas, and it is therefore necessary that accurate atomic data are calculated. It might be surprising, but a large fraction of the spectra produced by ions is still unexplored. Large discrepancies between observations and theory are also still present. For example, there are order-of-magnitude anomalies in the derived elemental abundances in H II regions and Planetary Nebulae. A mis-match between observation and theory is also present in the X-ray spectra of Active Galactic Nuclei (AGN). We intend to perform new calculations of electron-ion recombination rate coefficients to address these discrepancies. In recent years, we have shown the need to perform accurate R-matrix calculations of electron-ion collisions for individual ions, in order to solve the large, long-standing discrepancies between observed and calculated line intensities in collisional (astrophysical and laboratory) plasmas. We propose extending these calculations to all isolectronic sequences from H-like up to Na-like, providing a comprehensive and accurate dataset for all important ions. The theoretical data need to be assessed and benchmarked against astrophysical and laboratory measurements, in particular, in order to identify spectral lines and to provide accurate wavelengths and uncertainty estimates. We intend to provide all of these fundamental and derived data to the wider user community by setting up a web-based archive which will contain all of the atomic data needed to interpret, with physical modelling, the spectra of astrophysical and laboratory plasmas. With this proposal, we aim to strengthen the collaboration between experimental, observational and theoretical research.
Organisations
Publications
Liang G
(2009)
R -matrix inner-shell electron-impact excitation of the Na-like iso-electronic sequence
in Journal of Physics B: Atomic, Molecular and Optical Physics
Lukic D. V.
(2007)
Dielectronic recombination of Fe xv forming Fe xiv:: Laboratory measurements and theoretical calculations
in ASTROPHYSICAL JOURNAL
Madsen Chad A.
(2019)
Coronal Plasma Characterization via Coordinated Infrared and Extreme Ultraviolet Observations of a Total Solar Eclipse
in arXiv e-prints
Mulay S
(2017)
Cool and hot emission in a recurring active region jet
in Astronomy & Astrophysics
Mulay S
(2017)
Temperature and density structure of a recurring active region jet
in Astronomy & Astrophysics
Mulay S
(2016)
Multiwavelength study of 20 jets that emanate from the periphery of active regions
in Astronomy & Astrophysics
Polito V
(2016)
Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS
in Astronomy & Astrophysics
Schmidt E
(2008)
Electron-ion recombination for $\ion{Fe}{viii}$ forming $\ion{Fe}{vii}$ and $\ion{Fe}{ix}$ forming $\ion{Fe}{viii}$: measurements and theory
in Astronomy & Astrophysics
Song C
(2020)
Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: n = 4 Levels in P-like Ions from Mn xi to Ni xiv
in The Astrophysical Journal Supplement Series
Wang K
(2018)
Energy Levels, Lifetimes, and Transition Rates for P-like Ions from Cr x to Zn xvi from Large-scale Relativistic Multiconfiguration Calculations
in The Astrophysical Journal Supplement Series
Title | APAP |
Description | Atomic Data for Astrophysics |
Type Of Material | Database/Collection of data |
Provided To Others? | Yes |
Impact | Improved diagnostic modelling of astrophysical and magnetic fusion plasmas. |
URL | http://www.apap-network.org/ |