论文标题
压缩粘度和热导率在冠状环中慢速阻尼的情况下，没有加热冷却不平衡
Role of Compressive Viscosity and Thermal Conductivity on the Damping of Slow Waves in the Coronal Loops With and Without Heating-Cooling Imbalance
论文作者
论文摘要
在本文中，我们得出了一种新的分散关系，用于缓慢的磁性波，从而引起热导率，压缩粘度，辐射和未知加热项的影响，以及考虑线性MHD方程的加热冷却不平衡。我们解决了一般分散的关系，以了解压缩粘度和导热率在冠状环中慢波阻尼中的作用，无论有没有加热冷却不平衡。我们已经分析了环长度范围$ l $ = 50-500毫米，温度$ t $ = 5-30 mk和密度$ρ$ = 10 $^{ - 11} $ -10 $ -10 $^{ - 9} $ kg m $^{ - 3} $。发现包含压缩粘度以及导热率可显着增强较短模式振荡的阻尼（例如$ l $ = 50毫米）和Super-Hot（$ t> $ 10 MK）环路。但是，粘度在阻尼中的作用在更长的（例如$ l $ = 500毫米）和热环（T $ \ leq $ 10 mk）中微不足道，相反，导热率以及加热冷却不平衡的存在起着主要的作用。对于温度超热状态下的较短回路，循环密度的增加会大大增强由于缺乏粘度时导热率而导致的基本模式的阻尼，但是，当添加压缩粘度时，添加了密度的增加，密度的增加显着弱化阻尼。仅发现导热率在较低的温度下（t $ \ leq $ 10 mk）在较长的环中起主要作用，而压缩粘度在较短的环中以超热温度（$ t> $ 10 mk）的阻尼中占主导地位。在阻尼时间（$τ$）和波周期（$ p $）之间的预测缩放定律可以更好地与观察到的Sumer振荡匹配，而除了导热率和压缩粘度外，还考虑了加热冷却不平衡的情况，用于阻尼基本慢速模式振荡。
In the present paper, we derive a new dispersion relation for slow magnetoacoustic waves invoking the effect of thermal conductivity, compressive viscosity, radiation and unknown heating term along with the consideration of heating cooling imbalance from linearized MHD equations. We solve the general dispersion relation to understand role of compressive viscosity and thermal conductivity in damping of the slow waves in coronal loops with and without heating cooling imbalance. We have analyzed wave damping for the range of loop length $L$=50-500 Mm, temperature $T$=5-30 MK, and density $ρ$=10$^{-11}$-10$^{-9}$ kg m$^{-3}$. It was found that inclusion of compressive viscosity along with thermal conductivity significantly enhances the damping of fundamental mode oscillations in shorter (e.g., $L$=50 Mm) and super-hot ($T>$10 MK) loops. However, role of the viscosity in damping is insignificant in longer (e.g., $L$=500 Mm) and hot loops (T$\leq$10 MK) where, instead, thermal conductivity along with the presence of heating cooling imbalance plays a dominant role. For the shorter loops at the super-hot regime of the temperature, increment in loop density substantially enhances damping of the fundamental modes due to thermal conductivity when the viscosity is absent, however, when the compressive viscosity is added the increase in density substantially weakens damping. Thermal conductivity alone is found to play a dominant role in longer loops at lower temperatures (T$\leq$10 MK), while compressive viscosity dominates in damping at super-hot temperatures ($T>$10 MK) in shorter loops. The predicted scaling law between damping time ($τ$) and wave period ($P$) is found to better match to observed SUMER oscillations when heating cooling imbalance is taken into account in addition to thermal conductivity and compressive viscosity for the damping of the fundamental slow mode oscillations.
