On the coronal lines 5303 A and 6374 A

Abstract

Theoretical calculations of the observed coronal emission line profiles of Fe XIV (5303 A) and Fe X (6374 A) ions, which are observed at the time of total solar eclipse, are presented. Baumbach's relation of electron density has been employed to compute the FWHM. Several other electron density distributions have been employed, and it has been found that the calculated differences in the FWHM are within 0.5 percent of one another. To explain the observed FWHM, it has been assumed that the corona is expanding spherically symmetrically with a velocity on one or two mean thermal units and no turbulence is included. With these highly simplified assumptions, the profiles and FWHMs of the above lines have been reproduced qualitatively. However, to explain quantities of FWHMs, the inhomogeneities in the structure of the corona should be taken into account. It is thus shown that turbulence is not necessary to explain the observed FWHM.