Outflow speed of protons and O VI ions in a coronal hole
Abstract
In this work we estimate the outflow speed of protons and O VI ions as a function of latitude and heliocentric distance within a coronal hole. The outflow speed of protons is obtained from the mass flux conservation along the coronal magnetic field lines, while that of O VI ions is derived by applying the Doppler dimming technique to the intensity ratio of the O VI doublet lines at λλ1031.9 Å and 1037.6 Å, observed by the UVCS experiment. To this end we develop a 2D semiempirical coronal hole model, also based on UVCS data. We obtain that the outflow speed of these ions increases with the heliocentric distance, and with latitude from regions close to the equatorial streamer to the pole.
- Publication:
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Memorie della Societa Astronomica Italiana
- Pub Date:
- 2001
- Bibcode:
- 2001MmSAI..72..600Z
- Keywords:
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- Solar Coronal Holes