Spatial variation of periods of ion and neutral waves in a solar magnetic arcade

Context.We present a new insight into the propagation of ion magnetoacoustic and neutral acoustic waves in a magneticarcade in the lower solar atmosphere.Aims.By means of numerical simulations, we aim to: (a) study two-fluid waves propagating in a magnetic arcadeembedded in the partially-ionized, lower solar atmosphere; and (b) investigate the impact of the background magneticfield configuration on the observed wave-periods.Methods.We consider a 2D approximation of the gravitationally stratified and partially-ionized lower solar atmosphereconsisting of ion + electron and neutral fluids that are coupled by ion-neutral collisions. In this model, the convectionbelow the photosphere is responsible for the excitation of ion magnetoacoustic-gravity and neutral acoustic-gravitywaves.Results.We find that in the solar photosphere, where ions and neutrals are strongly coupled by collisions, ionmagnetoacoustic-gravity and neutral acoustic-gravity waves have periods ranging from250s to350s. In the chro-mosphere, where the collisional coupling is weak, the wave characteristics strongly depend on the magnetic field con-figuration. Above the foot-points of the considered arcade, the plasma is dominated by a vertical magnetic field alongwhich ion magnetoacoustic-gravity waves propagate. These waves exhibit a broad range of periods with the most promi-nent periods of180s,220s, and300s. Above the main loop of the solar arcade, where mostly horizontal magneticfield lines guide ion magnetoacoustic-gravity waves, the main spectral power reduces to the period of about180s andlonger wave-periods do not exist.Conclusions.In photospheric regions, ongoing solar granulation excites a broad spectrum of wave-periods that undergoescomplex interactions: mode-coupling, refractions through the inhomogeneous atmosphere, real physical absorption andconversion of wave power. We found that, in addition, the magnetic arcade configuration with a partially-ionized plasmadrastically changes the image of wave-periods observed in the upper layers of the chromosphere and corona. Our resultsare in agreement with the recent observational data reported by Wiśniewska et al. (2016) and Kayshap et al. (2018).

Publication year:2021

BOF-keylabel:yes

IOF-keylabel:yes

BOF-publication weight:2

CSS-citation score:1

Authors:International

Authors from:Higher Education

Accessibility:Open