An averaged transverse velocity of stochastic magnetic field lines between two tearing modes is presented by using the renormalized weak turbulence theory. The averaged velocity gives the friction coefficient of moving magnetic field lines which is expressed in terms of a renormalized propagator. A correlation length (time) of magnetic field lines, which is the time integrated renormalized propagator, is presented with respect to various parameters. The diffusion coefficient given in a previous paper (Sugimoto et al 1994 Plasma Phys. Control. Fusion 36 383) and the friction coefficient obtained here are related to each other by the so-called Einstein relation. Although the renormalized propagator given here involves more effects such as collision and friction types than that in the previous paper, which has the term of the diffusion type effect alone, the former effects do not greatly modify the renormalized propagator. Effects of collision and friction types do not play an important role in the propagator and the diffusion type effect alone is essential.
利用重正化弱湍流理论，给出了两个撕裂模之间随机磁力线的平均横向速度。该平均速度给出了运动磁力线的摩擦系数，该系数用重正化传播子表示。磁力线的相关长度（时间）是时间积分的重正化传播子，并针对各种参数给出。先前论文（Sugimoto 等，1994，等离子体物理与控制聚变，36，383）中给出的扩散系数与本文得到的摩擦系数通过所谓的爱因斯坦关系相互关联。尽管本文给出的重正化传播子包含了比先前论文中仅含扩散型效应项更多的效应，如碰撞型和摩擦型效应，但这些效应并未显著改变重正化传播子。碰撞型和摩擦型效应在传播子中不起重要作用，扩散型效应单独起主导作用。