dc.contributor.author |
O`Shea, E |
|
dc.contributor.author |
Banerjee, D |
|
dc.contributor.author |
Doyle, J. G |
|
dc.date.accessioned |
2006-01-17T06:06:30Z |
|
dc.date.available |
2006-01-17T06:06:30Z |
|
dc.date.issued |
2005-06 |
|
dc.identifier.citation |
Astronomy and Astrophysics, Vol. 436, No. 2, pp. L35 - L38 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/683 |
|
dc.description.abstract |
Using measurements of MgX 609.78 and 624.94 Å lines from the Coronal Diagnostic Spectrometer (CDS) on board
SOHO, we seek to examine the variation of line width and line ratio in regions far off-limb at the Northern pole of the Sun. It is
found that above ~1150" the ratio of the two coronal MgX resonance lines reduces to values that might be expected for a more
radiatively dominant excitation mode. A comparison of the line widths with these ratios indicates that the line widths start to
show a decrease in their values at the location where the dominant excitation changes from being collisionally to radiatively
dominant, that is, at ~1150". We suggest that the decrease in the line widths above ~1150" is likely to be due to a reduction in
the non-thermal component of the line widths caused by a damping of upwardly propagating Alfv´en waves. |
en |
dc.format.extent |
140088 bytes |
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dc.format.mimetype |
application/pdf |
|
dc.language.iso |
en |
en |
dc.publisher |
EDP Science |
|
dc.relation.uri |
http://dx.doi.org/10.1051/0004-6361:200500120 |
|
dc.rights |
© ESO |
|
dc.subject |
Sun: UV Radiation |
en |
dc.subject |
Sun: corona |
en |
dc.subject |
Sun:atmosphere |
en |
dc.title |
On the widths and ratios of MgX 609.79 and 624.94 Å lines in
polar off-limb regions |
en |
dc.type |
Article |
en |