On the Source of Propagating Slow Magnetoacoustic Waves in Sunspots

Krishna Prasad, S.; Jess, D. B.; Khomenko, E.
Referencia bibliográfica

The Astrophysical Journal Letters, Volume 812, Issue 1, article id. L15, 7 pp. (2015).

Fecha de publicación:
10
2015
Número de autores
3
Número de autores del IAC
1
Número de citas
47
Número de citas referidas
46
Descripción
Recent high-resolution observations of sunspot oscillations using simultaneously operated ground- and space-based telescopes reveal the intrinsic connection between different layers of the solar atmosphere. However, it is not clear whether these oscillations are externally driven or generated in situ. We address this question by using observations of propagating slow magnetoacoustic waves along a coronal fan loop system. In addition to the generally observed decreases in oscillation amplitudes with distance, the observed wave amplitudes are also found to be modulated with time, with similar variations observed throughout the propagation path of the wave train. Employing multi-wavelength and multi-instrument data, we study the amplitude variations with time as the waves propagate through different layers of the solar atmosphere. By comparing the amplitude modulation period in different layers, we find that slow magnetoacoustic waves observed in sunspots are externally driven by photospheric p-modes, which propagate upward into the corona before becoming dissipated.
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