The Propagation of Coherent Waves Across Multiple Solar Magnetic Pores

TL;DR

This study investigates how coherent magnetohydrodynamic waves propagate through solar magnetic pores from the photosphere to the chromosphere, revealing complex wave behaviors and partial coherence loss at higher atmospheric layers.

Contribution

It provides the first detailed analysis of wave propagation and coherence in multiple solar pores originating from the same sunspot, highlighting the complex wave dynamics and partial decoherence at chromospheric heights.

Findings

Universal presence of slow sausage mode oscillations in photospheric pores

Detection of wave power amplification as waves move into the chromosphere

Observation of wave decoherence and fractured wave guides at higher atmospheric layers

Abstract

Solar pores are efficient magnetic conduits for propagating magnetohydrodynamic wave energy into the outer regions of the solar atmosphere. Pore observations often contain isolated and/or unconnected structures, preventing the statistical examination of wave activity as a function of atmospheric height. Here, using high resolution observations acquired by the Dunn Solar Telescope, we examine photospheric and chromospheric wave signatures from a unique collection of magnetic pores originating from the same decaying sunspot. Wavelet analysis of high cadence photospheric imaging reveals the ubiquitous presence of slow sausage mode oscillations, coherent across all photospheric pores through comparisons of intensity and area fluctuations, producing statistically significant in-phase relationships. The universal nature of these waves allowed an investigation of whether the wave activity remained coherent as they propagate. Utilizing bi-sector Doppler velocity analysis of the Ca II 8542 {\AA} line, alongside comparisons of the modeled spectral response function, we find fine-scale 5 mHz power amplification as the waves propagate into the chromosphere. Phase angles approaching zero degrees between co-spatial bi-sectors spanning different line depths indicate standing sausage modes following reflection against the transition region boundary. Fourier analysis of chromospheric velocities between neighboring pores reveals the annihilation of the wave coherency observed in the photosphere, with examination of the intensity and velocity signals from individual pores indicating they behave as fractured wave guides, rather than monolithic structures. Importantly, this work highlights that wave morphology with atmospheric height is highly complex, with vast differences observed at chromospheric layers, despite equivalent wave modes being introduced into similar pores in the photosphere.