| Numéro |
J. Phys. Colloques
Volume 50, Numéro C1, Janvier 1989
International Conference on the Physics of Multiply Charged Ions and International Workshop on E.C.R. Ion Sources
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| Page(s) | C1-571 - C1-576 | |
| DOI | https://doi.org/10.1051/jphyscol:1989161 | |
J. Phys. Colloques 50 (1989) C1-571-C1-576
DOI: 10.1051/jphyscol:1989161
DIAGNOSTIC LINE RATIOS FOR HIGHLY IONIZED IONS OF THE BERYLLIUM ISOELECTRONIC SEQUENCE AND A COMPARISON WITH SOLAR OBSERVATIONAL DATA
S.M. McCANN1, F.P. KEENAN1 and K.G. WIDING21 Department of Pure and Applied Physics, Queen's University of Belfast, Belfast BT7 1NN, IR-Northern, Ireland
2 E.O. Hulburt Center for Space Research, Naval Research Laboratory, Washington DC, U.S.A.
Abstract
Observations of the relative line strengths of Beryllium like ions in a high temperature plasma can be used to derive the electron temperature and density of the emitting region through diagnostic line ratios [1, 2]. However, to calculate such ratios reliably, accurate atomic data must be employed, especially for the electron impact excitation rates of the relevant transitions [3]. In this paper we compare the theoretical S XIII and Ar XV emission line ratios R1 = I (2s2p 1P - 2s2 1S) / I (2s2p 3P1 - 2s2 1S), and R2 = I (2s2p 1P - 2s2 1S) / I (2p2 3P2 - 2s2p 3P2) with observational data for several solar flares, obtained using the SO82A instrument on board Skylab. Good agreement is found between theory and observation for R1 for both ions, which provides support for the electron impact excitation rates adopted in the calculations. However, in the case of R2, all the observed values for S XIII and Ar XV are much smaller than the theoretical estimates, which is probably due to blending in the 2p2 3P2 - 2s2p 3P2) lines.