Description
Inferring the polarisation state of coronal waves is key to understanding energy flux and dissipation in the outer solar atmosphere. By incorporating the polarisation, seismologists can improve constraints on the velocity amplitude and displacement estimates, leading to more accurate energy flux and deposition rates. We present a novel method to infer the polarisation of standing kink oscillations in coronal loops from a single viewpoint, using combined spectral and imaging data.
Applying this approach to observations from the Coronal Multi-channel Polarimeter (CoMP), we track the motion of a loop perturbed by an eruption, reconstructing its velocity-space phase portrait. Our analysis reveals a horizontally polarised $8.9 \pm 0.5$ minute period kink mode, in a plane tilted $-13.6^{+2.9}_{-3.0}$ degrees from the plane of sky. Periodic enhancements in line width are seen at both the kink period and its harmonic, which are signatures consistent with torsional Alfvén waves or shear-driven turbulence, pointing to potential energy dissipation mechanisms.
This methodology is particularly well suited to the capabilities of the upcoming MUSE mission, which will provide unprecedented multi-slit spectroscopic and imaging observations of the solar corona. When combined with the broad temperature coverage of Solar-C’s EUVST, this technique will maximise the information extracted from wave observations in the solar atmosphere, enabling systematic, high-cadence studies of wave-mode coupling and energy transport across the upper solar atmosphere.
