AAS 204th Meeting, June 2004
Session 29 The Solar Corona and Beyond
SPD Oral, Monday, May 31, 2004, 2:00-3:30pm, 702

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[29.03] The Linewidth Ratio of the O VI 1032 and 1037 Å Doublet in the Quiet Corona.

H. Morgan (Uni. of Wales, Aberystwyth, UK), S.R. Habbal ( CfA, Cambridge, USA.)

In observations of the quiet Corona with the Ultraviolet Coronagraph Spectrometer (UVCS) on SoHO the line width of the oxygen O VI 1031.9 Å consistently becomes smaller than the width of the O VI 1037.6 Å line at distances beyond 3 Rs. A model is used to show that this difference is due to the pumping of the O VI 1037.6 Å line by the two chromospheric C II lines at 1037 and 1036.3 Å. The model results are compared with two examples from observations to demonstrate that the larger width of the 1037.6 Å line is due to the differing line of sight contributions of the radiative components to each line. This study shows that the O VI linewidth ratio is a valuable diagnostic tool, which when used with the ratio of the intensities of the O VI lines, enables the inference of the outflow velocity of the oxygen ions in the inner corona.

The author(s) of this abstract have provided an email address for comments about the abstract: hhm01@aber.ac.uk

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