Gilchrist-Millar Caitlin A, Jess David B, Grant Samuel D T, Keys Peter H, Beck Christian, Jafarzadeh Shahin, Riedl Julia M, Van Doorsselaere Tom, Ruiz Cobo Basilio
Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330, USA.
Philos Trans A Math Phys Eng Sci. 2021 Feb 8;379(2190):20200172. doi: 10.1098/rsta.2020.0172. Epub 2020 Dec 21.
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 5 min were detected at varying atmospheric heights by examining Si ɪ 10827 Å 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 30 kW m at an atmospheric height of 100 km, dropping to approximately 2 kW m at an atmospheric height of around 500 km. 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 ≈ 268 km, 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'.
近年来，太阳孔隙作为磁波导管的适用性一直是讨论的关键话题。在此，我们展示了一组五个光球层太阳孔隙中传播的磁流体动力学波活动的观测证据。利用邓恩太阳望远镜的设施红外光谱偏振仪获得的数据，通过检查Si ɪ 10827 Å线平分线速度，在不同大气高度检测到了周期约为5分钟的振荡。光谱偏振反演结合空间分辨的均方根平分线速度，使得能够估计每个孔隙的波能通量随大气高度的变化。我们发现，在大气高度为100 km处，传播的磁声腊肠模波的能通量约为30 kW m，在大气高度约为500 km处降至约2 kW m。能通量的横截面结构揭示了体模和表面模腊肠波的存在。对能通量随大气高度衰减的研究提供了阻尼长度的估计值，发现所有五个孔隙的平均值约为268 km，与光球层密度标高相似。我们发现体模波的阻尼长度更长，这表明表面模腊肠振荡能够更轻易地耗散其嵌入的波能。这项工作验证了太阳孔隙在将磁声波能向上引导到太阳外层大气时作为有效导管的适用性。本文是西奥·墨菲会议特刊“太阳低层大气中的高分辨率波动动力学”的一部分。
