Query : 2016A&A...592A.135F

2016A&A...592A.135F - Astronomy and Astrophysics, volume 592A, 135-135 (2016/8-1)

Scaling of collision strengths for highly-excited states of ions of the H- and He-like sequences.


Abstract (from CDS):

Emission lines from highly-excited states (n≥5) of H- and He-like ions have been detected in astrophysical sources and fusion plasmas. For such excited states, R-matrix or distorted wave calculations for electron-impact excitation are very limited, due to the large size of the atomic basis set needed to describe them. Calculations for n≥6 are also not generally available. We study the behaviour of the electron-impact excitation collision strengths and effective collision strengths for the most important transitions used to model electron collision dominated astrophysical plasmas, solar, for example. We investigate the dependence on the relevant parameters: the principal quantum number n or the nuclear charge Z. We also estimate the importance of coupling to highly-excited states and the continuum by comparing the results of different sized calculations. We provide analytic formulae to calculate the electron-impact excitation collision strengths and effective collision strengths to highly-excited states (n≥8) of H- and He-like ions. These extrapolated effective collision strengths can be used to interpret astrophysical and fusion plasma via collisional-radiative modelling.

Abstract Copyright: © ESO, 2016

Journal keyword(s): atomic data - Sun: corona - techniques: spectroscopic

VizieR on-line data: <Available at CDS (J/A+A/592/A135): si13_t1.dat si13_t2.dat si13_t3.dat s15_t1.dat s15_t2.dat s15_t3.dat>

Simbad objects: 0

goto Full paper

goto View the references in ADS

Number of rows : 0

To bookmark this query, right click on this link: simbad:objects in 2016A&A...592A.135F and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact