The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere
The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere
复制标题
混合引起的冷却在太阳大气的质量和能量循环中的作用
DOI：
10.1093/mnras/stad234
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发表时间：
2023
影响因子：
4.8
通讯作者：
Hillier A
中科院分区：
文献类型：
--
作者：
Hillier A
在许多天体物理系统中，通过Kelvin-Helmholtz不稳定性驱动的湍流，冷和热温度气体/等离子体之间的混合导致中间温度相的形成，增加了驱动有效冷却的辐射损失。太阳大气层是一个潜在的网站，这一过程发生的日珥或针状材料和日冕之间的相互作用，允许过渡区的材料与增强的辐射损失的发展。在本文中，我们推导出一组方程来模拟这种混合层的演变，并预测混合驱动的冷却速率和混合导致日冕物质冷凝的速率。这些理论预测的基准对2.5D MHD模拟。将理论标度应用于日珥线或褪色的针状物，我们发现，当混合层在它们的边界上生长时，这将导致过渡区材料的产生，冷却时间为100 s，这解释了观测到的温暖发射，因为日珥线或针状物在冷光谱线中褪色，而不需要任何加热。对于静止的日珥，由混合过程驱动的动态凝结可以恢复日珥通过下降流损失的18%的质量。总的来说，这种通过混合引起的辐射损失的热能损失机制突出了在试图理解日冕中冷物质的热力学演化时考虑不同温度下物质之间的动力学相互作用的重要性。
In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin–Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive efficient cooling. The solar atmosphere is a potential site for this process to occur with interaction between either prominence or spicule material and the solar corona allowing the development of transition region material with enhanced radiative losses. In this paper, we derive a set of equations to model the evolution of such a mixing layer and make predictions for the mixing-driven cooling rate and the rate at which mixing can lead to the condensation of the coronal material. These theoretical predictions are benchmarked against 2.5D MHD simulations. Applying the theoretical scalings to prominence threads or fading spicules, we found that as a mixing layer grows on their boundaries this would lead to the creation of transition region material with a cooling time of ∼100 s, explaining the warm emission observed as prominence threads or spicules fade in cool spectral lines without the requirement for any heating. For quiescent prominences, dynamic condensation driven by the mixing process could restore ∼18 per cent of the mass lost from a prominence through downflows. Overall, this mechanism of thermal energy loss through radiative losses induced by mixing highlights the importance for considering dynamical interaction between material at different temperatures when trying to understand the thermodynamic evolution of the cool material in the solar corona.
理想 MHD 不稳定性，重点关注瑞利-泰勒和开尔文-亥姆霍兹不稳定性
DOI：
--
发表时间：
2019
期刊：
Topics in Magnetohydrodynamic Topology, Reconnection and Stability Theory
影响因子：
--
作者：
A. Hillier
通讯作者：
A. Hillier