Abdulrahman Albidah

Gather.town id
DSO05
Poster Title
Novel techniques for identifying magnetohydrodynamic wave modes in sunspot umbrae in the DKIST era.
Institution
Majmaah University, Saudi Arabia
Abstract (short summary)
In this work, we applied POD and DMD techniques to identify the dominant MHD wave modes in sunspot umbrae. The sunspot intensity time series employed in this study were acquired using the Hydrogen-Alpha Rapid Dynamics camera at the Dunn Solar Telescope (DST). The POD technique was used to find modes that are spatially orthogonal, whereas the DMD technique identifies temporal orthogonality. It was found that the combined POD and DMD approaches can be successfully used for MHD modes detection. With the DKIST era now upon us, these same techniques can be applied to much higher resolution data, allowing us to probe the fine structure of sunspot umbrae with local helioseismology.
Plain text (extended) Summary
High-resolution observations of pores and sunspots show a rich and complex variety of oscillatory temporal and spatial behaviour. To decompose this data into individual magnetohydrodynamic (MHD) wave modes is non-trivial and requires a multi-faceted approach. We apply the proper orthogonal decomposition (POD) and Dynamic Mode decomposition (DMD) techniques to identify the dominant MHD wave modes in a sunspot using intensity time series. POD classifies modes that are orthogonal in space, but places no restrictions on their frequencies. DMD has no such spatial restrictions, but classifies modes that are orthogonal in time, i.e. the identified modes cannot have the same frequency. Here we show that the combined POD and DMD approaches can successfully identify both sausage and kink modes in a sunspot umbra with an approximately circular cross-sectional shape.
URL
Contact me on a.albedah@mu.edu.sa or abalbidah1@sheffield.ac.uk