Speaker
Description
Coronal fan loops rooted in sunspot umbra constantly show a 3-min period propagating slow magnetoacoustic waves (SMAWs) in the corona (upper solar atmosphere). Using the recently devised technique of Rawat & Gupta (2023), we trace these loops along with their cross-sectional area with height from the photosphere to the corona via the transition region and chromosphere (lower solar atmosphere). We estimated the relative amplitude and energy flux of propagating 3-min SMAWs in the lower and upper solar atmosphere along the fan loops. We obtained their damping length of 208 km and 4.3 Mm in the lower and upper atmosphere, respectively. We further investigated the role of the area expansion of these loops on the damping of these SMAWs. We deduced the decay of total wave energy content within the loop cross-sectional area with height and estimated the damping length to be 303 km in the lower atmosphere. Henceforth, we present the first report on the actual damping of SMAWs after incorporating the geometric effect of area expansion of the loops. Findings reveal that the area expansion of loops with height plays an important role in the damping of these waves in the lower atmosphere, while the effect is negligible in the upper atmosphere. These actual damping lengths can be utilized to investigate the dominant damping mechanisms in the lower (photosphere to corona) and upper solar atmosphere (corona).
| Sessions | Wave generation, energy transport, dissipation and heating |
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