论文标题
星际介质中弱磁湍流的热阻尼
Thermal damping of Weak Magnetosonic Turbulence in the Interstellar Medium
论文作者
论文摘要
我们提出了一种通用机制，用于由于辐射冷却而产生的星际介质（ISM）中压缩波的热阻尼。我们求解在两流体（离子中性）系统中磁波的分散关系，其中存在密度和温度依赖性加热和冷却机制。除了对非线性湍流级联反应的分析近似外，我们还使用这种分散关系来模拟弱磁湍流的耗散。我们表明，在某些ISM条件下，当将热阻尼添加到常规的离子中性阻尼中时，磁性湍流的截止波长变为数十万倍。我们还运行了数值模拟，这些模拟证实了这种效果对压缩波模式的级联反应产生巨大影响。
We present a generic mechanism for the thermal damping of compressive waves in the interstellar medium (ISM), occurring due to radiative cooling. We solve for the dispersion relation of magnetosonic waves in a two-fluid (ion-neutral) system in which density- and temperature-dependent heating and cooling mechanisms are present. We use this dispersion relation, in addition to an analytic approximation for the nonlinear turbulent cascade, to model dissipation of weak magnetosonic turbulence. We show that in some ISM conditions, the cutoff wavelength for magnetosonic turbulence becomes tens to hundreds of times larger when the thermal damping is added to the regular ion-neutral damping. We also run numerical simulations which confirm that this effect has a dramatic impact on cascade of compressive wave modes.
