UK APAP Network

"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 the satellite missions such as SOHO, Hinode, STEREO, SDO (solar) and Chandra, XMM-Newton, HST, FUSE (non-solar).
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 characterizing 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.
In recent years, we have shown the need to perform accurate 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 a series of calculations which will enable us to interpret spectral data from these satellites which will further our understanding of the solar corona, stellar atmospheres, supernova remnants, nebulae and stars.
With this proposal, we aim to strengthen the collaboration between experimental, observational and theoretical research. Our work will also impact upon the magnetic fusion program and its quest for a safe, reliable and environmentally friendly energy source."