Wave propagation in a solar quiet region and the influence of the magnetic canopy

TL;DR

This study investigates how the magnetic canopy in the solar quiet region influences wave propagation, revealing mode conversion, transmission effects, and the impact of magnetic structures on wave behavior in the photosphere and chromosphere.

Contribution

It provides new evidence of wave transmission and mode conversion at the magnetic canopy, using phase difference analysis in different solar regions.

Findings

Magnetic canopy lowers phase differences of progressive waves.

Waves with frequencies below the acoustic cut-off can propagate.

Indications of wave response in Doppler signals affected by magnetic structures.

Abstract

Aims. We seek indications or evidence of transmission/conversion of magnetoacoustic waves at the magnetic canopy, as a result of its impact on the properties of the wave field of the photosphere and chromosphere. Methods. We use cross-wavelet analysis to measure phase differences between intensity and Doppler signal oscillations in the Halpha, CaII H, and G-band.We use the height of the magnetic canopy to create appropriate masks to separate internetwork (IN) and magnetic canopy regions. We study wave propagation and differences between these two regions. Results. The magnetic canopy affects wave propagation by lowering the phase differences of progressive waves and allowing the propagation of waves with frequencies lower than the acoustic cut-off. We also find indications in the Doppler signals of Halpha of a response to the acoustic waves at the IN, observed in the CaII H line. This response is affected by the presence of the magnetic canopy. Conclusions. Phase difference analysis indicates the existence of a complicated wave field in the quiet Sun, which is composed of a mixture of progressive and standing waves. There are clear imprints of mode conversion and transmission due to the interaction between the p-modes and small-scale magnetic fields of the network and internetwork.