Non-linear evolution of instabilities between dust and sound waves
Non-linear evolution of instabilities between dust and sound waves
复制标题
尘埃和声波之间不稳定性的非线性演化
DOI：
10.1093/mnras/stz2128
复制
发表时间：
2019
影响因子：
4.8
通讯作者：
Hopkins, Philip F
中科院分区：
文献类型：
--
作者：
Moseley, Eric R;Squire, Jonathan;Hopkins, Philip F
我们研究了非线性演化的声学共振阻力不稳定性（RDI），使用数值模拟。当尘埃颗粒流过气体时，在尘埃-气体混合物中激发声学RDI，与声波相互作用以引起线性不稳定性。我们在周期性盒子中研究了这个过程，通过外部驱动力加速中性尘埃。不稳定性如线性理论所预测的那样增长，最终分裂成湍流并饱和。在线性理论中，非线性行为的特点是由三个制度-高，中，低波数-之间的边界是由粉尘-气体的耦合强度和粉尘-气体的质量比。高和中间波数制度的行为彼此相似，大的灰尘气体比波动，而气体仍然在很大程度上不可压缩。饱和状态是高度各向异性的：尘埃沿加速方向沿着聚集成细丝、射流或羽流，湍流涡旋状结构在垂直方向上迅速形成和消散。低波数制度表现出气体和尘埃密度的大波动，但尘埃和气体仍然更强烈地耦合在垂直于加速度的相干“前线”。这些行为与外部流体动力学湍流“被动”驱动的尘埃有质的不同，尘埃对气体没有反作用力。这些不稳定性的致命性质对各种天体物理系统中的尘埃驱动风有着有趣的影响，包括冷恒星周围，活动星系核周围的尘埃鸟居，以及巨大分子云内部和周围。
We study the non-linear evolution of the acoustic ‘resonant drag instability’ (RDI) using numerical simulations. The acoustic RDI is excited in a dust–gas mixture when dust grains stream through gas, interacting with sound waves to cause a linear instability. We study this process in a periodic box by accelerating neutral dust with an external driving force. The instability grows as predicted by linear theory, eventually breaking into turbulence and saturating. As in linear theory, the non-linear behaviour is characterized by three regimes – high, intermediate, and low wavenumbers – the boundary between which is determined by the dust–gas coupling strength and the dust-to-gas mass ratio. The high and intermediate wavenumber regimes behave similarly to one another, with large dust-to-gas ratio fluctuations while the gas remains largely incompressible. The saturated state is highly anisotropic: dust is concentrated in filaments, jets, or plumes along the direction of acceleration, with turbulent vortex-like structures rapidly forming and dissipating in the perpendicular directions. The low-wavenumber regime exhibits large fluctuations in gas and dust density, but the dust and gas remain more strongly coupled in coherent ‘fronts’ perpendicular to the acceleration. These behaviours are qualitatively different from those of dust ‘passively’ driven by external hydrodynamic turbulence, with no back-reaction force from dust on to gas. The virulent nature of these instabilities has interesting implications for dust-driven winds in a variety of astrophysical systems, including around cool stars, in dusty torii around active-galactic-nuclei, and in and around giant molecular clouds.
登录
查看更多内容
甘道夫 - N 体动力学和拉格朗日流体的图形天体物理学代码
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
D. Hubber;G. Rosotti;R. Booth
通讯作者：
R. Booth
磁化分子云中带电尘埃的动力学
影响因子：
4.8
作者：
Hyunseok Lee;P. Hopkins;J. Squire
通讯作者：
J. Squire
磁化气体中灰尘运动普遍存在的不稳定性
影响因子：
4.8
作者：
P. Hopkins;J. Squire
通讯作者：
J. Squire
共振阻力不稳定性 (RDI)：声学模式
影响因子：
4.8
作者：
Hopkins, Philip F;Squire, Jonathan
通讯作者：
Squire, Jonathan
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell