Issue |
A&A
Volume 387, Number 3, June I 2002
|
|
---|---|---|
Page(s) | 1092 - 1099 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361:20020310 | |
Published online | 17 May 2002 |
Solar
-modes and surface magnetic fields:
Is there an acoustic emission?
MDI/SOHO observations
1
Department of Physics, UMIST, Manchester M60 1QD, UK e-mail: rjain@suraj.phy.umist.ac.uk
2
JILA, University of Colorado, Boulder, CO 80309-440, USA e-mail: dhaber@solarz.colorado.edu
Corresponding author: R. Jain, rjain@suraj.phy.umist.ac.uk
Received:
18
July
2001
Accepted:
28
February
2002
We study the effect of magnetism on the surface amplitude of p-modes by creating power maps using Doppler velocity, line-depth and continuum intensity data taken by the Michelson Doppler Interferometer (MDI) instrument on board SOHO. This analysis, using proper tracking procedures, of MDI line-depth data and its comparison with the simultaneous Doppler velocity data is the first such analysis. All three datasets show that the p-mode power is suppressed in the magnetic region with suppression increasing with field strength. However, in the high-frequency range, the power is enhanced in the Doppler velocity and line-depth data but not in continuum intensity. This enhancement, when present, appears to be in intermediate field strength elements in the immediate vicinity of a magnetically active region.
Key words: Sun: helioseismology, oscillations, magnetic fields, photosphere, sunspots / methods: data analysis
© ESO, 2002
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