论文标题
粘性原星磁盘中流不稳定性的效率有多高？
How efficient is the streaming instability in viscous protoplanetary disks?
论文作者
论文摘要
流媒体不稳定性是通过集中灰尘颗粒引发重力崩溃的流行候选。但是，它对原行星磁盘预期的物理条件的鲁棒性尚不清楚。特别是，通过湍流搅拌的粒子可能会阻碍不稳定。为了量化这种效果，我们使用气体粘度和颗粒扩散模型的外部湍流发展了流型不稳定性的线性理论。我们发现流媒体不稳定性对湍流很敏感，其增长率对于alpha-viscosity参数$α\ gtrsim \ gtrsim \ mathrm {st} ^{1.5} $而言，$ \ mathrm {st} $是粒子编号。我们探讨了非线性阻力定律的效果，该法律可能适用于多孔灰尘颗粒，并发现生长速率适度降低。我们还发现，气体可压缩性通过减少扩散效应来提高生长速率。然后，我们将线性理论应用于粘性原球磁盘的全局模型。对于最小质量太阳星云磁盘模型，我们发现流媒体不稳定性仅在磁盘寿命内生长，即使是$ \ sim 10 $ au的$ \ sim 10 $ s，即使对于CM尺寸的颗粒和弱湍流（$α\ SIM 10^{ - 4} $）。我们的结果表明，很难触发非层流原球磁盘的流态不稳定性，尤其是对于小颗粒。
The streaming instability is a popular candidate for planetesimal formation by concentrating dust particles to trigger gravitational collapse. However, its robustness against physical conditions expected in protoplanetary disks is unclear. In particular, particle stirring by turbulence may impede the instability. To quantify this effect, we develop the linear theory of the streaming instability with external turbulence modelled by gas viscosity and particle diffusion. We find the streaming instability is sensitive to turbulence, with growth rates becoming negligible for alpha-viscosity parameters $α\gtrsim \mathrm{St} ^{1.5}$, where $\mathrm{St}$ is the particle Stokes number. We explore the effect of non-linear drag laws, which may be applicable to porous dust particles, and find growth rates are modestly reduced. We also find that gas compressibility increase growth rates by reducing the effect of diffusion. We then apply linear theory to global models of viscous protoplanetary disks. For minimum-mass Solar nebula disk models, we find the streaming instability only grows within disk lifetimes beyond $\sim 10$s of AU, even for cm-sized particles and weak turbulence ($α\sim 10^{-4}$). Our results suggest it is rather difficult to trigger the streaming instability in non-laminar protoplanetary disks, especially for small particles.
