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Observation and modeling of the umbra of sunspot AR 12470 using ALMA and BBSO data

Published onJun 01, 2020
Observation and modeling of the umbra of sunspot AR 12470 using ALMA and BBSO data

Waves and oscillations are an enduring topic in the study of the solar atmosphere since they have been considered an important candidate for solving the coronal heating problem. For decades, numerous efforts in observation and modeling have been put forth, yet the complexity of the solar atmosphere has left many questions unanswered . Now that the Atacama Large Millimeter/submillimeter Array (ALMA) has become available, we have entered a new era when it is possible to directly probe the chromospheric temperature variation on very short (1-2 s) timescales. Combined with some solar dedicated instruments, such as Goode Solar Telescope (GST) at the Big Bear Solar Observatory (BBSO), we are able to carry out high spatial and temporal observations that target the sunspot umbra, so that they can provide additional guidance to sunspot modeling. We present a study of umbral waves and oscillations in the sunspot AR12470 using the data from both ALMA and BBSO that were taken on December 17, 2015. With the help of fourier analysis, we found the locations of the maximum power of the 3-min oscillation signal in the sunspot umbra at ALMA band 3 (3 mm) wavelength. We found a stable phase relation between ALMA band 3 temperature variations and Hα intensities at various wavelengths in the line, taken with the GST. With the help of these data, we model the waves as a perturbation of the existing 1D solar models by Fontenla et al. and the numerical radiative transfer RH (Rybicki & Hummer) code. The detailed information and discussion are in the poster.

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