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Skylab Observations of Temperature and Density Sensitive Emission Line Ratios in Ne VI

Published online by Cambridge University Press:  12 April 2016

C.J. Greer ,
V.J. Foster ,
F.P. Keenan ,
R.H.G. Reid ,
J.G. Doyle ,
H.L. Zhang  and
A.K. Pradhan
C.J. Greer
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, Northern Ireland
V.J. Foster
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, Northern Ireland
F.P. Keenan
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, Northern Ireland
R.H.G. Reid
Affiliation:
Department of Applied Mathematics and Theoretical Physics, The Queen’s University of Belfast, Belfast BT7 INN, Northern Ireland
J.G. Doyle
Affiliation:
Armagh Observatory, Armagh BT61 9DG, Northern Ireland
H.L. Zhang
Affiliation:
Department of Astronomy, Ohio State University, Columbus, Ohio 43210, USA
A.K. Pradhan
Affiliation:
Department of Astronomy, Ohio State University, Columbus, Ohio 43210, USA

Abstract

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Recent calculations of electron and proton impact excitation rates in Ne VI are used to derive the intensity ratios of lines in the ~402–1006 Å wavelength range as a function of electron temperature (Te) and density (Ne). These results are presented in the form of ratio-ratio diagrams, which should in principle allow both Ne and Te to be deduced for the Ne VI line emitting region of a plasma. Electron temperatures and densities derived from ratio-ratio diagrams involving the 562.7, 997.4, 999.6 and 1006.1 Å lines, in conjunction with observational data for a sunspot obtained with the Harvard S-0555 spectrometer on board Skylab, are found to be compatible, and in good agreement with plasma parameters determined using other methods. This provides some support for the diagnostic calculations presented in this paper, and hence the atomic data used in their derivation. However agreement between theory and observation is very poor for other Ne VI lines in the sunspot spectrum, and for most transitions observed in S-0555 active region and flare data, which is probably due to blending with lines from N III, Mg VI and Mg VII. The application of the calculations to non-solar EUV sources is discussed.

Type
XII. The Solar/Stellar Connection in the EUV
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 537 - 541
Copyright
Copyright © Kluwer 1996

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