Magnetoacoustic wave energy dissipation in the atmosphere of solar pores

The suitability of solar pores as magnetic wave guides has been a key topic of discussion in recent years. Here, we present observational evidence of propagating magnetohydrodynamic wave activity in a group of five photospheric solar pores. Employing data obtained by the Facility Infrared Spectropolarimeter at the Dunn Solar Telescope, oscillations with periods of the order of 5min were detected at varying atmospheric heights by examining Si ? 10827 angstrom line bisector velocities. Spectropolarimetric inversions, coupled with the spatially resolved root mean square bisector velocities, allowed the wave energy fluxes to be estimated as a function of atmospheric height for each pore. We find propagating magnetoacoustic sausage mode waves with energy fluxes on the order of 30kWm(-2) at an atmospheric height of 100km, dropping to approximately 2kWm(-2) at an atmospheric height of around 500km. The cross-sectional structuring of the energy fluxes reveals the presence of both body- and surface-mode sausage waves. Examination of the energy flux decay with atmospheric height provides an estimate of the damping length, found to have an average value across all five pores of L-d approximate to 268km, similar to the photospheric density scale height. We find the damping lengths are longer for body mode waves, suggesting that surface mode sausage oscillations are able to more readily dissipate their embedded wave energies. This work verifies the suitability of solar pores to act as efficient conduits when guiding magnetoacoustic wave energy upwards into the outer solar atmosphere. This article is part of the Theo Murphy meeting issue 'High-resolution wave dynamics in the lower solar atmosphere'.

Automated summary

Observational evidence of magnetohydrodynamic wave activity in solar pores is presented, with energy fluxes decreasing at higher atmospheric heights, suggesting solar pores can efficiently guide wave energy upwards. The study highlights the presence of both body- and surface-mode sausage waves in solar pores.