ALMA环中的粉尘生长：II. 含尘罗斯贝波不稳定性
Dust Growth in ALMA Rings: II. Dusty Rossby Wave Instability
AI总结：
研究ALMA环内粉尘生长的含尘罗斯贝波不稳定性，通过双流体方程线性分析识别出I型和II型两种DRWI模式，并基于DSHARP源评估发现I型模式可解释盘内方位角不对称缺失，II型模式在观测环中完全不存在。
AI中文摘要：
环形子结构是星子形成的理想场所。在本系列研究中，我们探讨了环内粉尘生长的线性阶段。第一篇论文研究了全局流动不稳定性，而本研究聚焦于含尘罗斯贝波不稳定性（DRWI）。我们在背景压力凸起上对双流体方程进行线性分析，以表征环形子结构。使用谱代码Dedalus求解线性特征值问题。我们识别出两种截然不同的DRWI模式：I型，源于粉尘修正的气体RWI；II型，由粉尘-气体耦合产生。对于给定的方位角波数$\ky$，这些模式从不共存，而是随着$\ky$变化而相互转换。I型模式由背景涡度的平流驱动，而II型模式涉及两种主要波：由平流驱动的罗斯贝波和由粉尘-气体拖曳驱动的薄波。最后，我们使用DSHARP源评估了DRWI在ALMA环中的相关性。研究结果表明，I型模式可以解释许多ALMA盘中方位角不对称性的缺失，而II型模式在所有八个观测环中完全不存在，这表明未分辨的窄环或其他机制可能在环形子结构内的粉尘生长中发挥作用。
英文摘要：
Annular substructures serve as ideal venues for planetesimal formation. In this series, we investigate the linear stage of dust growth within rings. The first paper examines the global streaming instability, while this study focuses on the dusty Rossby wave instability (DRWI). We perform a linear analysis of the two-fluid equations on a background pressure bump, representing annular substructures. The spectral code \textsc{Dedalus} is used to solve the linear eigenvalue problem. We identify two distinct DRWI modes: Type I, which originates from dust-modified gas RWI, and Type II, which results from dust-gas coupling. These modes never coexist for a given azimuthal wavenumber $\ky$, but transition between each other as $\ky$ varies. Type I modes are driven by the advection of background vorticity, whereas Type II modes involve two primary waves: Rossby waves, driven by advection, and thin waves, driven by dust-gas drag. Finally, we assess the relevance of DRWI in ALMA rings using DSHARP sources. Our findings suggest that Type I modes could explain the absence of azimuthal asymmetries in many ALMA disks, whereas Type II modes are entirely absent in all eight observed rings, implying that unresolved narrow rings or alternative mechanisms may play a role in dust growth within annular substructures.
