Wave Propagation and Jet Formation in the Chromosphere

TL;DR

This study uses numerical simulations to analyze wave propagation and jet formation in the solar chromosphere, highlighting the importance of magnetic field inclination and the effectiveness of wavelet analysis over Fourier methods.

Contribution

It provides new insights into how magnetic field inclination influences wave periods and jet formation, with detailed simulations including radiative losses and wave analysis techniques.

Findings

5-minute waves dominate in inclined magnetic regions

3-minute waves are prevalent in vertical field regions

Wavelet analysis better captures temporal variations

Abstract

We present the results of numerical simulations of wave propagation and jet formation in solar atmosphere models with different magnetic field configurations. The presence in the chromosphere of waves with periods longer than the acoustic cutoff period has been ascribed to either strong inclined magnetic fields, or changes in the radiative relaxation time. Our simulations include a sophisticated treatment of radiative losses, as well as fields with different strengths and inclinations. Using Fourier and wavelet analysis techniques, we investigate the periodicity of the waves that travel through the chromosphere. We find that the velocity signal is dominated by waves with periods around 5 minutes in regions of strong, inclined field, including at the edges of strong flux tubes where the field expands, whereas 3-minute waves dominate in regions of weak or vertically oriented fields. Our results show that the field inclination is very important for long-period wave propagation, whereas variations in the radiative relaxation time have little effect. Furthermore, we find that atmospheric conditions can vary significantly on timescales of a few minutes, meaning that a Fourier analysis of wave propagation can be misleading. Wavelet techniques take variations with time into account and are more suitable analysis tools. Finally, we investigate the properties of jets formed by the propagating waves once they reach the transition region, and find systematic differences between the jets in inclined field regions and those in vertical field regions, in agreement with observations of dynamic fibrils.