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| Paper: |
Interaction of Helioseismic Waves with Sunspots: Observations
and Numerical MHD Simulations |
| Volume: |
462, Progress in Solar/Stellar Physics with Helio- and Asteroseismology |
| Page: |
277 |
| Authors: |
Zhao, J.; Parchevsky, K. V.; Kosovichev, A. G. |
| Abstract: |
We investigate how helioseismic waves that originate from effective point
sources interact with sunspots. For observations, the waves from point
sources are reconstructed by cross-correlating observed photospheric
Doppler signals. For numerical simulations, the waves are generated by
simulating perturbation propagation from a pulse near the surface
and propagate through magnetostatic and magnetohydrodynamic (MHD) sunspot models. For both cases,
we study f-mode and p-mode waves separately. We also study
different cases when the point source is located outside the sunspot,
and when the source is located inside the sunspot. Our results nicely
visualize how the waves, including both wave amplitudes and phases,
interact with the magnetic field, thermodynamic and flow structure
of sunspots, and how the waveform evolves before, during, and after
the propagation through sunspots. Our analysis of wave–magnetic-field
interactions also extends below the sunspot's surface. This brings us
new rich information of how the waves respond to the magnetic field
below the surface, but also poses new challenges for local helioseismology
to infer the sunspot's interior properties from waveform observations. |
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