AI 中文总结
研究原行星盘中尘埃陷阱问题，考虑大规模磁场应力对气体旋转速度影响，通过模拟发现磁场使大颗粒向内漂移速度增加，能抵消向外漂移打开尘埃陷阱，揭示磁场对尘埃聚集和流不稳定有阻止或更严格限制作用。
AI 中文摘要
原行星盘中观测到的环状结构常被解释为局部压力最大值，可导致有效的尘埃聚集。我们重新审视这一范式，考虑大规模磁场应力对气体旋转速度的影响。模拟表明，磁场在动力学上很强，在典型的含粒径大于1μm尘埃颗粒的湍流盘中，其边缘处与开普勒旋转的偏差可达1 - 2%。这使斯托克斯数为0.01 - 0.1的大颗粒向内漂移速度增加两倍。这种磁流体动力学与开普勒旋转的偏差不依赖于局部气体压力梯度，仅导致朝向恒星的漂移。其引起的快速漂移可抵消环内边缘正压力梯度导致的向外漂移，打开尘埃陷阱。对于湍流参数α = 10⁻³的盘，此效应出现在半宽为10 au、密度对比度高达60%（α = 10⁻²时为200%）的环中。因此，原行星盘中大规模磁场的存在要么完全阻止要么对尘埃聚集和密度环中流不稳定的发生施加更严格条件。
英文摘要
Observed ring-like structures in protoplanetary disks are often interpreted as local pressure maxima, which induce efficient dust concentration. We revisit this paradigm, considering the effect of the large-scale magnetic field stresses on the gas rotation speed. Our simulations show that the magnetic field can be dynamically strong and cause $1-2$% deviation from the Keplerian rotation at the periphery of a typical turbulent disk with dust grains of size $> 1\,μ$m. This effect increases the inward drift speed of large grains characterized by Stokes number of $0.01-0.1$ by up to two times in our simulations. Importantly, such MHD deviation from the Keplerian rotation does not depend on the local gas pressure gradient and leads to drift towards the star only. The fast drift induced by this effect can cancel out the outward drift caused by the positive pressure gradient at the inner edge of a ring and open up the dust trap. For the disks with turbulence parameter $α=10^{-3}$, this effect appears in the rings with a half-width of $10$ au and a density contrast up to $60$% ($200$% for $α=10^{-2}$). Thus, the presence of a large-scale magnetic field in protoplanetary disks either completely prevents or imposes stricter conditions for dust accumulation and the onset of the streaming instability in the density rings in protoplanetary disks.
Comments17 pages, 8 figures, 2 tables, accepted to ApJ
