Bibcode
Olshevsky, V.; Khomenko, E.; Collados, M.
Bibliographical reference
"Modern solar facilities - advanced solar science, Proceedings of a Workshop held at Göttingen September 27-29, 2006 ISBN 978-3-938616-84-0 382 pages, many illustrations, soft-bound, Price: 23.- Euros Published by Universitätsverlag Göttingen (http://univerlag.uni-goettingen.de The online edition (PDF, 12 MB) is available free of charge at: http://webdoc.sub.gwdg.de/univerlag/2007/solar_science_book.pdf, p.347"
Advertised on:
0
2007
Citations
1
Refereed citations
1
Description
We present the first results of a 3D numerical modeling of linear MHD
wave propagation in a realistic sunspot model. In our simulations, a
piston located at the base of the photosphere generates waves with a
certain period. The ratio between the acoustic and the Alfven speed, cS
/vA, decreases from much larger than one at the photosphere to much
lower than one in the chromosphere in our simulation domain. Waves
propagate through the region where cS << vA, where mode
transformation is observed. At a somewhat higher region, where cS = vA,
the fast (magnetic) mode reflects back to the photosphere due to the
vertical and horizontal gradients of vA. The slow (acoustic) mode
propagates to the upper layers and increases its velocity amplitude.
Unlike the 2D simulations, the Alfven mode is also generated by the
piston and experiences transformations at the cS = vA layer. The
behaviour of this mode requires further study.