Abstracts Details


First Name * : Sowmya
Last Name * : Krishnamurthy
Affiliation * : Max Planck Institute for Solar System Research
Abstract Type * : Oral
Title * : Chromosphere above sunspot umbra
Author(s) * : Sowmya Krishnamurthy, Alexander I. Shapiro, Natalie A. Krivova, Rinat V. Tagirov, Sami K. Solanki
Abstract Session * : Science with future facilities
Abstract * : 1D semi-empirical models of solar atmosphere play an important role in modeling of the solar irradiance variability. However, the chromospheric parts of magnetic features such as the sunspots remain poorly represented in those models. This is particularly critical for the far UV (ultra-violet) irradiance which forms in the chromosphere. Lack of adequate observational constraints so far hindered building of realistic umbral models. Recently, ALMA (Atacama Large Millimeter/sub-millimeter Array) provided observations of a sunspot in radio wavelengths of 1.3 and 3 mm. The height of formation of the emission at 3 mm corresponds well to the formation height of the 1330 and 1400\,\AA{} emissions observed by the IRIS (Interface Region Imaging Spectrograph). We use these ALMA data together with the radio observations from JCMT (James Clerk Maxwell Telescope) to build a model of the chromosphere above a sunspot umbra, accounting for the deviations of electron number density from the LTE (local thermodynamic equilibrium). IRIS data can provide additional constraints for the model. Such a model is useful not only for proper modeling of the solar irradiance but also for interpreting the anticipated sunspot observations from SUNRISE 3 and Aditya-L1 missions.