arXiv subjects

Samuel J. Skirvin

Publications and source records attributed to Samuel J. Skirvin.

2 recordsLinked to original sources

arXiv2026

The Influence of Opacity on Inferred MHD Wave Signatures in the Lower Solar Atmosphere

Magnetohydrodynamic wave activity in small-scale magnetic structures, such as solar pores, provides key insights into energy transport in the lower solar atmosphere. This study presents high-resolution observations of ten solar pores contained within a 43 x 43 Mm$^2$ field of view, obtained with the CRISP instrument at the Swedish 1-m Solar Telescope. We investigate the temporal behaviour of the line-of-sight velocity (vlos) and magnetic field (blos) oscillations within the pore structures. Using SIR inversions, we analyse the oscillatory signals at multiple optical depths (log $τ$ levels) to assess how variations in geometric height (z) and temperature relate to the observed blos fluctuations. Our results reveal that higher-frequency oscillations (> 6 mHz) exhibit strong coherences with in-phase fluctuations between blos and z across atmospheric layers, consistent with upward-propagating magneto-acoustic waves. In contrast, coherent lower-frequency oscillations display significant phase differences, which may arise from opacity effects contaminating the inversion response. These findings highlight the importance of accounting for opacity effects when interpreting magnetic oscillations, with direct implications for forthcoming high-precision magnetic diagnostics from facilities such as DKIST.

astro-ph.SR↗

arXiv2023

Modelling of transverse oscillations driven by p-modes in short coronal loops

Recent observations have revealed two types of decayless transverse oscillations in short coronalloops: one with short periods scaling with loop lengths, and the other with longer periods that exhibit a peak at around 5 min in the period distribution. To understand such a difference in period, we work in the framework of ideal MHD and model a short coronal loop embedded in an atmosphere with density stratification from the chromosphere to the corona. An inclined p-mode-like driver with a period of 5 min is launched at one loop footpoint. It is discovered that two types of decayless transverse oscillations can be excited in the loop. We interpret the 5 min periodicity as being directly driven by the footpoint driver, while the others, with periods of several tens of seconds, are regarded as kink eigenmodes of different harmonics. Therefore, our simulation shows that both types of decayless oscillations found in observations can be excited by p-modes in one short coronal loop. This study extends our understanding of ubiquitous decayless transverse oscillations in the corona. Furthermore, it suggests that p-modes could be an important energy source for coronal heating by driving decayless transverse oscillations.

astro-ph.SR↗