Instabilities and Flow Structures in Protoplanetary Disks: Setting the Stage for Planetesimal Formation.
Instabilities and Flow Structures in Protoplanetary Disks: Setting the Stage for Planetesimal Formation.
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原行星盘中的不稳定性和流动结构：为星子形成奠定基础。
DOI：
10.1007/978-3-319-55333-7_138
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Schreiber
中科院分区：
文献类型：
--
作者：
H. Klahr;Thomas Pfeil;A. Schreiber
本章重点介绍原行星盘中湍流和中尺度流动结构的性质及其在行星形成过程中的作用。在这里，我们专注于从卵石云引力坍缩的星子的形成。大规模和长寿命的流结构-涡和带状流-是弱磁和流体动力学不稳定性的压力和熵分层准开普勒剪切流与磁盘的快速旋转相互作用的结果。另一方面，涡旋和纬向流是进入圆盘径向卵石通量的粒子陷阱，导致局部足够的积累引发引力坍缩，直接将卵石转化为许多公里大小的微行星。这种崩溃是缓和的流动的不稳定性，这是一个反反应，从颗粒积聚到气流。在没有捕获卵石并因此增加局部固气比的情况下，这种反反应最终将通过湍流扩散阻止行星的形成。因此，长寿命的流动结构的形成是一个必要的条件，一个有效的和快速形成的星子。
This chapter highlights the properties of turbulence and meso-scale flow structures in protoplanetary disks and their role in the planet formation process. Here we focus on the formation of planetesimals from a gravitational collapse of a pebble cloud. Large scale and long lived flow structures - vortices and zonal flows - are a consequence of weak magneto and hydrodynamic instabilities in the pressure and entropy stratified quasi-Keplerian shear flow interacting with the fast rotation of the disk. The vortices and zonal flows on the other hand are particle traps tapping into the radial pebble flux of the disk, leading to locally sufficient accumulations to trigger gravitational collapse, directly converting pebbles to many kilometer sized planetesimals. This collapse is moderated by the streaming instability, which is a back-reaction from the particle accumulations onto the gas flow. Without trapping pebbles and increasing thus the local solid to gas ratio, this back-reaction would ultimately prevent the formation of planetsimals via turbulent diffusion. The formation of long lived flow structures is therefore a necessary condition for an efficient and fast formation of planetesimals.
吸积盘垂直剪切不稳定性的线性和非线性演化
影响因子：
4.8
作者：
Nelson R
通讯作者：
Nelson R