首页 | 本学科首页   官方微博 | 高级检索  
     


Extreme ultraviolet transitions of Fe xxi in solar, stellar and laboratory spectra
Authors:F.P. Keenan  K.M. Aggarwal  D.R. Williams  M. Mathioudakis  K.J.H. Phillips
Affiliation:1Department of Pure and Applied Physics, Queen's University, Belfast BT7 1NN; 2Space Science &Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX
Abstract:Recent R -matrix calculations of electron impact excitation rates for transitions among the 2s22p2, 2s2p3 and 2p4 levels of Fe  xxi are used to derive theoretical electron density ( N e) sensitive emission-line ratios involving 2s22p2–2s2p3 transitions in the ∼98–146Å wavelength range. A comparison of these with observations from the PLT tokamak plasma, for which the electron density has been independently determined, reveals generally very good agreement between theory and experiment, and in some instances removes discrepancies found previously. The observed Fe  xxi ratios for a solar flare, obtained with the OSO–5 satellite, imply electron densities which are consistent, with discrepancies that do not exceed 0.2 dex. In addition, the derived values of N e are similar to those estimated for the high-temperature regions of other solar flares. The good agreement between theory and observation, in particular for the tokamak spectra, provides experimental support for the accuracy of the present line-ratio calculations, and hence for the atomic data on which they are based.
Keywords:plasmas    Sun: UV radiation
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号