We consider fast magnetic reconnection that takes place within turbulent magnetic flux and show that the process results in diffusion of magnetic fields and matter, which we term reconnection diffusion. The process of reconnection diffusion is based on the model of 3D reconnection of weakly turbulent magnetic fields and is applicable to both fully ionized and partially ionized gas. The rate of reconnection diffusion does not depend on the level of ionization and therefore the usually employed ambipolar diffusion idea gets irrelevant for magnetic field transport in turbulent fluids. We claim that the reconnection diffusion process is a manifestation of the violation of flux conservation in highly conducting turbulent fluids. We discuss the consequences of reconnection diffusion for star formation and stress. We show that reconnection diffusion on large scales is independent of small scale magnetic field dynamics of magnetic fields. We conclude that numerical simulations correctly represents the diffusion of actual astrophysical magnetic fields in flows with substantially larger Lundquist numbers if these simulated regions regions are turbulent.
Disc formation in turbulent cloud cores: is magnetic flux loss necessary to stop the magnetic braking catastrophe or not?
Santos-Lima、de Gouveia Dal Pino和Lazarian（2012年）最近对湍流磁化云核中开普勒盘形成的数值分析表明，重联扩散是一个有效的过程，可以在旋转支撑盘的形成过程中去除多余的磁通量。这个过程是由湍流中磁场的快速重联引起的。在一项类似的数值研究中，Seifried等人（2012年）得出结论，重联扩散或任何其他非理想MHD效应都是不必要的，仅湍流剪切就可以提供一种自然的方式来建立旋转盘，而不需要磁通量损失。他们的结论是基于这样一个事实，即在半径远大于圆盘的球形区域上计算的平均质量通量比（μ）在他们的模型中几乎是恒定的。在这封信中，我们比较了两组模拟，并表明这种在大尺度上的平均可以掩盖在圆盘形成的内部区域μ的显着实际增加。我们表明，在吸积的湍流包络材料中，在盘形成的初始阶段发生了磁场的重联扩散。我们的分析是暗示，重连扩散是存在于这两套模拟，并提供了一个简单的解决方案的“磁制动灾难”，这是在文献中讨论的形成原恒星吸积盘。
