Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/5946
Title: Properties of High-Frequency Wave Power Halos Around Active Regions: An Analysis of Multi-height Data from HMI and AIA Onboard SDO
Authors: Rajaguru, S. P
Couvidat, S
Sun, Xudong
Hayashi, K
Schunker, H
Keywords: Active regions;Magnetic fields;Chromosphere;Helioseismology;Photosphere;Magnetohydrodynamics;Sunspots;Waves, acoustic
Issue Date: Oct-2013
Publisher: Springer
Citation: Solar Physics, Vol. 287, No. 1-2, pp. 107-127
Abstract: We study properties of waves of frequencies above the photospheric acoustic cut-off of ≈5.3 mHz, around four active regions, through spatial maps of their power estimated using data from the Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The wavelength channels 1600 Å and 1700 Å from AIA are now known to capture clear oscillation signals due to helioseismic p-modes as well as waves propagating up through to the chromosphere. Here we study in detail, in comparison with HMI Doppler data, properties of the power maps, especially the so-called “acoustic halos” seen around active regions, as a function of wave frequencies, inclination, and strength of magnetic field (derived from the vector-field observations by HMI), and observation height. We infer possible signatures of (magneto)acoustic wave refraction from the observation-height-dependent changes, and hence due to changing magnetic strength and geometry, in the dependencies of power maps on the photospheric magnetic quantities. We discuss the implications for theories of p-mode absorption and mode conversions by the magnetic field.
Description: Restricted Access
The original publication is available at springerlink.com
URI: http://hdl.handle.net/2248/5946
ISSN: 1573-093X
???metadata.dc.rights???: © Springer
???metadata.dc.relation.uri???: http://dx.doi.org/10.1007/s11207-012-0180-9
http://rd.springer.com/article/10.1007%2Fs11207-012-0180-9?null
Appears in Collections:IIAP Publications

Files in This Item:
File Description SizeFormat 
Properties of High-Frequency Wave Power Halos Around Active Region.pdfRestricted Access1.51 MBAdobe PDFView/Open    Request a copy


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.