发表机构
Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM; Institute of Space Sciences (ICE), CSIC（巴黎萨克雷大学，巴黎西岱大学，法国原子能和替代能源委员会，法国国家科学研究中心，天体物理、分子和星际介质实验室; 空间科学研究所，西班牙国家研究委员会）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究构建考虑尘埃惯性的带电尘埃多流体模型，明确原恒星坍缩中气体、尘埃与磁场的耦合退耦条件，拓展了磁流体力学模型适用范围，为相关非线性效应研究提供理论基础。
AI 中文摘要
星际尘埃在恒星与行星形成中发挥关键作用，包括原恒星坍缩过程中气体与磁场的耦合，这些作用取决于局域尘埃粒径分布，需对带电尘埃采用多流体处理。本研究旨在理解尘埃分布与气体、磁场相互作用的动力学基础物理，尤其要明确各组分的耦合与退耦条件。我们构建了考虑尘埃惯性的带电尘埃多流体模型，采用化学网络模拟坍缩原恒星核中的电荷平衡；计算阿尔文模式与磁声波模式，以理解气体、尘埃流体与磁场间的耦合机制，并与现有中性尘埃多流体模型、标准非理想磁流体动力学模型的预测结果对比。带电多流体模型在坍缩致密核与形成盘的大尺度上与非理想磁流体动力学一致，且成功拓展至尘埃惯性起关键作用的新 regime（区域）。我们发现高荷质比尘埃携带原恒星包层中磁流体力学波的传播，给出了依赖尘埃分布的波速解析表达式；磁压缩扰动会在天文单位尺度引发局域尘埃-气体比变化，在非线性 regime（区域）提供了带电尘埃分布动力学的理论理解，其封闭磁流体力学方程组可植入数值代码，用于探索原恒星坍缩中的非线性效应，如湍流、角动量输运及磁性尘埃团块形成。
英文摘要
Interstellar grains play key roles in star and planet formation, including the coupling of the gas to the magnetic field during the protostellar collapse. These roles depend on the local grain size distribution, which requires a multifluid treatment of charged dust. We aim to understand the fundamental physics of the dynamics of a dust distribution in interaction with the gas and the magnetic field. In particular, the purpose is to characterize the (de)coupling conditions of these different components. We provide a multifluid model of charged dust which accounts for the inertia of the grains. A chemical network is used to simulate the charge equilibrium in collapsing protostellar cores. We compute the Alfven modes and the magnetosonic modes to understand the coupling regimes between the gas, the dust fluids, and the magnetic field. We also analyze and compare to the predictions of existing models, that are the neutral dust multifluid and the standard non-ideal magnetohydrodynamics. The charged multifluid model agrees with non-ideal magnetohydrodynamics on the larger scales of a collapsing dense core and the forming disk, while we successfully extend to new regimes where the inertia of dust grains matters. We found that high charge-to-mass dust grains carry the propagation of magnetohydrodynamical waves in protostellar envelopes. We provide analytical expressions of the speed of these waves depending on the dust distribution. The magnetocompressive perturbations lead to local dust-to-gas ratio variations at au scales. A theoretical understanding of the dynamics of a charged dust distribution is provided in the linear regime. The closed set of magnetohydrodynamics equations can be implemented in numerical codes to explore nonlinear effects during the protostellar collapse such as turbulence, angular momentum transport and magnetic dust clumping.
CommentsAccepted for publication in Astronomy & Astrophysics
