Astronomy and Astrophysics – Astrophysics
Scientific paper
Apr 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000a%26a...356..335d&link_type=abstract
Astronomy and Astrophysics, v.356, p.335-338 (2000)
Astronomy and Astrophysics
Astrophysics
10
Sun: Activity, Sun: Corona, Sun: General, Sun: Transition Region, Sun: Uv Radiation
Scientific paper
Full disk images from SUMER/SoHO taken in He I, C IV and Ne VIII are used to investigate whether there exists a center-to-limb variation in the line width. Both C IV and He I show such a variation but the higher temperature Ne VIII line is relatively constant. For C IV, this corresponds to ~ 3 km s-1 difference while He I is significantly larger particularly at the limb. This work may suggest that the non-thermal motions are slightly non-isotropic in the transition region and upper chromosphere, with the horizontal unresolved motions exceeding those in the vertical plane however a more probable explanation is that the lines are broadened due to opacity effects. The more slower variation in the C IV 1548 Ä line width could be explained by increasing the opacity from zero at disk center to ~ 1 at the limb. For He I the opacity is significantly grater than unity at the limb. This therefore implying all mass motions in the chromosphere, transition region and corona are isotropic.
Banerjee Dipti
Doyle Gerry J.
Teriaca Luca
No associations
LandOfFree
Solar transition region line broadening: Limb to limb measurements does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Solar transition region line broadening: Limb to limb measurements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solar transition region line broadening: Limb to limb measurements will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-747814