论文标题
在原星磁盘的层流模型中的电加热和角动量传输
Electric heating and angular momentum transport in laminar models of protoplanetary disks
论文作者
论文摘要
原星磁盘的垂直温度结构在与行星形成有关的几个过程中，例如气体和尘土化学，冰线和对流。温度曲线由中央恒星的辐射和任何内部热源（例如气体积聚产生）控制。我们研究了层状磁盘中磁场的电阻耗散产生的热量和角动量转运。我们使用局部一维模拟来获得内磁盘中典型条件（0.5至4 au）的垂直温度曲线。使用简单的假设对气体电离和不透明度，加热和冷却速率是在辐射性非理想磁流失动力学的框架内自兼而有的。我们表征了与中平面对称的稳定溶液，并且可能与饱和的Hall剪切不稳定模式有关。我们还研究了由全球积极驱除结构驱动的电流的耗散。在这两种情况下，我们都能获得足够高的不透明度的大量加热。强磁场可以诱导磁盘中平面，对流不稳定的熵曲线以及表面发射率的订单不升高，等于$α\ sim 10^{ - 2} $的粘性加热。这些结果表明，磁场如何在湍流可能效率低下的弱离子磁盘上驱动有效的积聚和加热，至少对于一系列半径和磁盘年龄，磁场如何驱动磁场。
The vertical temperature structure of a protoplanetary disk bears on several processes relevant to planet formation, such as gas and dust grain chemistry, ice lines and convection. The temperature profile is controlled by irradiation from the central star and by any internal source of heat such as might arise from gas accretion. We investigate the heat and angular momentum transport generated by the resistive dissipation of magnetic fields in laminar disks. We use local one-dimensional simulations to obtain vertical temperature profiles for typical conditions in the inner disk (0.5 to 4 au). Using simple assumptions for the gas ionization and opacity, the heating and cooling rates are computed self-consistently in the framework of radiative non-ideal magnetohydrodynamics. We characterize steady solutions that are symmetric about the midplane and which may be associated with saturated Hall-shear unstable modes. We also examine the dissipation of electric currents driven by global accretion-ejection structures. In both cases we obtain significant heating for a sufficiently high opacity. Strong magnetic fields can induce an order-unity temperature increase in the disk midplane, a convectively unstable entropy profile, and a surface emissivity equivalent to a viscous heating of $α\sim 10^{-2}$. These results show how magnetic fields may drive efficient accretion and heating in weakly ionized disks where turbulence might be inefficient, at least for a range of radii and ages of the disk.
