UV line intensity and flow velocity distributions in two coronal mass ejections as deduced by UVCS-SOHO observations

TitleUV line intensity and flow velocity distributions in two coronal mass ejections as deduced by UVCS-SOHO observations
Publication TypeJournal Article
Year of Publication2002
AuthorsVentura, R., Spadaro D., Uzzo M., and Suleiman R.
JournalAstronomy and Astrophysics
Volume383
Pagination1032-1048
Date PublishedMar
Abstract

The Ultraviolet Coronagraph Spectrometer (UVCS) instrument onboard the SOHO satellite observed two coronal mass ejections on November 2 and 3, 2000, related to the eruptions of a large filament structure in an active region close to the West limb of the Sun, and of a prominence near the South Pole, respectively. Intensity and profile of the O VI resonance doublet lines at 1032 and 1037 Å and of Lybeta (1026 Å) line, together with the intensity of some other minor ions, were observed using the O VI channel of UVCS. We analysed these spectroscopic observations in order to get information about the distributions of ionic densities and flow velocities in the solar coronal plasma ejected during these transient events. Emission in ions ranging from C II to O VI indicates a temperature range between 10$^{4.5}$ and 10$^{5.5}$ K. The morphology of the bright emission regions suggests the development of several strands of plasma irregularly distributed inside the CME structures, whose temporal evolution is significantly different from each other. The velocities determined for each bright element also give a complex picture of the plasma kinematics characterizing these coronal mass ejections.

DOI10.1051/0004-6361:20011802