Variation of acoustic cutoff period with height in the solar atmosphere: theory versus observations

TL;DR

This study combines observations and numerical simulations to investigate how the acoustic cutoff frequency varies with height in the solar atmosphere, revealing discrepancies with existing theories and providing a new method to determine atmospheric structure.

Contribution

The paper presents numerical simulations that successfully reproduce observed variations of the acoustic cutoff frequency with height, addressing limitations of previous theoretical formulas.

Findings

Numerical results agree well with observational data.

Existing theoretical formulas do not account for observed variations.

The method can be used to determine solar atmospheric structure.

Abstract

Recently Wi\'sniewska et al. demonstrated observationally how the acoustic cutoff frequency varies with height in the solar atmosphere including the upper photosphere and the lower and middle chromosphere, and showed that the observational results cannot be accounted for by the existing theoretical formulas for the acoustic cutoff. In order to reproduce the observed variation of the cutoff with atmospheric height, numerical simulations of impulsively generated acoustic waves in the solar atmosphere are performed, and the spectral analysis of temporal wave profiles is used to compute numerically changes of the acoustic cutoff with height. Comparison of the numerical results with the observational data shows good agreement, which clearly indicates that the obtained results may be used to determine the structure of the background solar atmosphere.