Investigating the observational signatures of non-linear damping of MHD kink waves

Back and forth oscillations, associated with the MHD kink wave, are present in magnetic structures throughout the solar atmosphere. These waves potentially provide an important energy source to heat the solar corona and properties of the waves have been be used to infer important physical quantities, e.g. magnetic field strength, in the solar corona.

Observationally, of particular importance is the rate at which these waves damp as it provides information on the rate at which energy is being extracted from the oscillating wave and potentially the mechanism behind the extraction. Recent theoretical work has highlighted the importance of non-linearities in extracting energy from large-scale MHD kink waves which can result in their damping and potentially drive enhanced energy dissipation.

However, when connecting this new theory to the observations, there has been no development beyond linear concepts to make any comparison. This is fundamentally flawed as the non-linear evolution of a kink wave will be different from the evolution under the assumption of linearity, meaning there is a currently a gap between the assumptions of wave theory and how it is applied.

Kink waves provide a wealth of information about the physics of the solar corona. Therefore, to only apply linear tools to interpret kink wave observations will mean we misinterpret this information. In this project we will detail how damping of MHD kink waves through non-linear physics manifests in observations and how to interpret this information.

To do this we will focus on answering three questions: What are the damping profiles predicted by non-linear damping mechanisms? What are the observational signatures of these mechanisms? And can evidence be found in the observational data to support the existence of wave damping by non-linear processes in the solar atmosphere?

To answer these questions we will develop and test analytic models of non-linear damping. Then through forward modelling of MHD simulations predict the observational signatures of these damping mechanisms. Finally we will search for these signatures in observational data to quantify the frequency with which non-linear processes lead to MHD kink wave damping in the solar atmosphere.