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Title: | Sunspot seismology: accounting for magnetohydrodynamic wave processes using imaging spectropolarimetry |
Authors: | Rajaguru, S. P |
Keywords: | sunspots – Sun: helioseismology – MHD |
Issue Date: | 2011 |
Publisher: | Astronomical Society of India |
Citation: | ASI Conference Series, Vol. 2, pp. 181–188 |
Abstract: | E ects of acoustic wave absorption, mode conversion and transmission by a sunspot on the helioseismic inferences are widely discussed, yet accounting for them has proved di cult for lack of a consistent framework within helioseismic modelling. Here, following a discussion of problems and issues that the near-surface magnetohydrodynamics hosts through a complex interplay of radiative transfer, measurement issues, and MHD wave processes, I present some possibilities entirely from observational analyses based on imaging spectropolarimetry. In particular, I present some results on wave evolution as a function of observation height and inclination of magnetic field to the vertical, derived from a high-cadence imaging spectropolarimetric observation of a sunspot and its surroundings using the instrument IBIS (NSO/Sac Peak, USA). These observations were made in magnetically sensitive (Fe I 6173 Å) and insensitive (Fe I 7090 Å) upper photospheric absorption lines. Wave travel time contributions from within the photospheric layers of a sunspot estimated here would then need to be removed from the inversion modelling procedure, that does not have the provision to account for them. |
Description: | Open Access |
URI: | http://hdl.handle.net/2248/5700 |
ISBN: | 978-81-922926-0-1 |
Appears in Collections: | IIAP Publications |
Files in This Item:
File | Description | Size | Format | |
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Sunspot seismology.pdf | 239.62 kB | Adobe PDF | View/Open |
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