Research Projects

High-frequency acoustic waves generated in the interior of the Sun can propagate in the outer solar atmosphere but get rapidly damped below chromosphere due to radiative losses. However, in magnetised atmospheres, they get transformed into magneto-acoustic modes and propagate all the way up to corona before eventually dissipating there due to high thermal conduction and other physical mechanisms. The magneto-acoustic waves are often probed for their relevance for the solar atmospheric heating and for their unique application as seismological tools. While the Alfven waves are difficult to dissipate, the slow modes are known to be readily dissipated in the solar atmosphere. Recent studies reveal a significant reduction in the energy of slow waves before they reach the outer atmosphere. This decay is possibly due to radiative losses and shock dissipation but must also include other dissipationless energy losses such as that due to reflection and mode conversion. It is very puzzling to find that despite the additional energy losses in the magnetised atmospheres, these waves actually reach the outer layers. A proper quantitative description of individual loss mechanisms is necessary to evaluate the true dissipation and thereby understand this puzzle. Furthermore, a comprehensive understanding on their propagation and dissipation is necessary to utilise the observed properties of these waves for seismology. We plan to achieve this using coordinated ground- and space-based observations including multi-height spectropolarimetric data in combination with numerical simulations. Understanding the role of different MHD waves in solar atmospheric heating is one of the primary goals of all modern solar missions (including Aditya-L1, the first Indian solar space mission that is due to be launched this year), so the relevance of this project in the national and international context is evident.