Speaker
Description
First Name: Samuel
Last Name: Skirvin
Affiliation: Northumbria University
All Authors: Samuel Skirvin, Richard Morton
Abstract: Magnetohydrodynamic (MHD) waves are abundant throughout the solar atmosphere. Their prevalence in the solar corona positions them as leading candidates to contribute to the heating of local plasma, ultimately accelerating the solar wind and producing EUV radiation. Recent high-resolution spectroscopic observations of coronal loops from DKIST-CryoNIRSP have revealed small-scale torsional oscillations, known as torsional Alfvén waves, with small wave amplitudes (<0.1 km/s), alongside the routinely observed transverse (Alfvénic) motions. In this work, we wish to numerically model the co-existence of both transverse and torsional waves in coronal loop threads in a 3D numerical model, using the PLUTO code. We conduct forward modelling in the Fe XIII (1074.7 nm) line using the pyCELP code to compare the synthetic Stokes vectors, Doppler velocity and line width with those of the observations. Using fundamental properties of the Alfvénic waves, we reveal the small-scale torsional motions present in the forward modelling, with heavily reduced amplitudes due to the line-of-sight integration. The reduced line-of-sight Doppler velocities have implications for estimating the energy content of these waves. We explore the possibility to infer the real wave amplitudes in the observations from the synthetic output data.