Solar Physics

, Volume 92, Issue 1, pp 75–79

Theoretical emission line ratios for O vii in low-density plasmas

  • F. P. Keenan
  • S. S. Tayal
  • A. E. Kingston
Article

DOI: 10.1007/BF00157236

Cite this article as:
Keenan, F.P., Tayal, S.S. & Kingston, A.E. Sol Phys (1984) 92: 75. doi:10.1007/BF00157236

Abstract

New electron excitation rates for O vii calculated by Tayal and Kingston using the R-matrix method are used to determine theoretical emission line strengths. Values of the electron density sensitive ratio R (forbidden line to intercombination line) are found to be very similar to those deduced by other authors. However the temperature sensitive ratios G (intercombination plus forbidden lines to resonance line) are approximately 20% lower than the best previous estimates. The observed value of G for solar active regions (G = 1.0 ± 0.1) predicts an electron temperature in the range 1.1 × 106 K < Te < 1.8 × 106 K, which overlaps that of maximum O vii emissivity, TM = 1.8 × 106 K. In addition, the theoretical G versus Te curve is in excellent agreement with that observed for a Tokamak plasma.

Copyright information

© D. Reidel Publishing Company 1984

Authors and Affiliations

  • F. P. Keenan
    • 1
  • S. S. Tayal
    • 1
  • A. E. Kingston
    • 1
  1. 1.Department of Applied Mathematics and Theoretical PhysicsThe Queens University of BelfastBelfastN. Ireland
  2. 2.Department of PhysicsD. J. College, Baraut, University of MeerutMeerutIndia