Solar Physics

, Volume 181, Issue 1, pp 91–101

Coronal line-width variations

  • J. G. Doyle
  • D. Banerjee
  • M. E. Perez
Article

Abstract

Line-width measurements of the coronal ion Siviii confirm earlier observations which show an increase in the non-thermal velocity above the solar limb. The present data, taken at the equatorial limb, show an increase from 24 km s-1 at the limb to 28 km s-1 some 25000 km above the limb. The electron density as measured from the Siviii line pair shows a decrease from 3.5 × 108 cm-3 to 1.8 × 108 cm-3 over the same distance. These data imply that the non-thermal velocity is inversely proportional to the quadratic root of the electron density, in excellent agreement with that predicted for undamped radially propagating Alfvén waves.

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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • J. G. Doyle
    • 1
  • D. Banerjee
    • 1
  • M. E. Perez
    • 1
  1. 1.Armagh ObservatoryArmaghN. Ireland

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