Growth of magnetorotational instability in circumstellar discs around class 0 protostars
Growth of magnetorotational instability in circumstellar discs around class 0 protostars
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DOI：
10.1093/mnras/stab1224
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发表时间：
2021-05-21
影响因子：
4.8
通讯作者：
Machida, Masahiro N.
中科院分区：
文献类型：
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作者：
Kawasaki, Yoshihiro;Koga, Shunta;Machida, Masahiro N.
我们研究了0级原恒星周围的磁旋转不稳定性（MRI）增长的可能性。我们建立了一个圆盘模型，并计算了中性和带电原子、分子和尘埃颗粒的化学反应，从而得出了每种物质的丰度和圆盘的电离度。然后，我们估计了非理想磁流体力学效应如欧姆耗散、双极性扩散和霍尔效应的扩散系数。最后，我们评估MRI在椎间盘各区域的线性增长速度。我们在圆盘模型中考察了磁场强度和方向的变化对扩散系数的影响，并采用四种不同的粉尘模型考察了粉尘粒径分布对扩散系数的影响。我们的结果表明，在远离原恒星的区域可能存在一个弱磁场的MRI活跃区，在那里霍尔效应在MRI的生长中起作用。另一方面，在所有模型中，椎间盘在内部区域的MRI是稳定的
We investigate the possibility of the growth of magnetorotational instability (MRI) in discs around Class 0 protostars. We construct a disc model and calculate the chemical reactions of neutral and charged atoms, molecules, and dust grains to derive the abundance of each species and the ionization degree of the disc. Then, we estimate the diffusion coefficients of non-ideal magnetohydrodynamics effects such as ohmic dissipation, ambipolar diffusion, and the Hall effect. Finally, we evaluate the linear growth rate of MRI in each area of the disc. We investigate the effect of changes in the strength and direction of the magnetic field in our disc model and we adopt four different dust models to investigate the effect of dust size distribution on the diffusion coefficients. Our results indicate that an MRI-active region possibly exists with a weak magnetic field in a region far from the protostar where the Hall effect plays a role in the growth of MRI. On the other hand, in all models, the disc is stable against MRI in the region within