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Anomalous effects on classical and neoclassical transport

对古典和新古典交通的异常影响

基本信息

批准号：
15560718
负责人：
TAGUCHI Masayoshi
金额：
$ 0.77万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

We have investigated the plasma transport due to fluctuations using a renormalization technique of statistical dynamics and obtained the following results :1.Employing a functional integral method, we have studied the particle diffusion in a stochastic magnetic field. With the ensemble average of a functional representation to a kinetic equation over the fluctuating magnetic field and the random variables modeling the Coulomb collisions, a closed set of equations for an ensemble-averaged distribution function and a response function to an infinitesimal external perturbation is derived within the framework of the direct-interaction approximation (DIA). It is found from these equations that the cross-field diffusion coefficients can be obtained by solving nonlinear ordinary differential equations. We have explicitly calculated diffusion coefficients for various parameters in the shearless and sheared configurations.2.We have theoretically studied the effect of fluctuations on the bootstr … More ap current in tokamaks. Based upon a closed set of equations for the ensemble-averaged distribution function and the response function, we have derived a radial diffusion equation for the bootstrap current density. The anomalous radial diffusion due to fluctuations as well as the finite-banana width effect is shown to significantly modify the conventional bootstrap current near the magnetic axis. It is also shown that this modification leads to the possibility of a completely bootstrapped tokamak. The radial diffusion equation for the rf-driven current density is also obtained using the similar method.3.Applying the DIA to subensemble-averaged functions instead of conventional ensemble-averaged ones, we have derived a closed set of equations for a subensemble-averaged distribution function and its response function. This closure theory approximately provides the Lagrangian description by incorporating particle trajectory effect. The running diffusion coefficient in turbulent plasma is shown to be calculated by solving a nonlinear ordinary differential equation together with an equation for deterministic particle trajectories. Less

我们利用统计动力学的重整化技术研究了等离子体在波动下的输运，得到了以下结果：用泛函积分的方法研究了随机磁场中粒子的扩散。在直接相互作用近似（DIA）的框架下，利用脉动磁场上动力学方程的函数表示的系综平均和库仑碰撞的随机变量，导出了系综平均分布函数和对无限小外部扰动的响应函数的闭方程组。从这些方程中发现，可以通过求解非线性常微分方程得到跨场扩散系数。我们明确地计算了无剪切和受剪切两种构型下各种参数的扩散系数。我们从理论上研究了波动对托卡马克自举电流的影响。基于集合平均分布函数和响应函数的封闭方程组，导出了自举电流密度的径向扩散方程。由于波动引起的异常径向扩散以及有限香蕉宽度效应显著地改变了磁轴附近的常规自举电流。还表明，这种改进使完全自举托卡马克成为可能。用同样的方法得到了射频驱动电流密度的径向扩散方程。将DIA应用于子集合平均函数而不是传统的集合平均函数，得到了子集合平均分布函数及其响应函数的闭方程组。该闭包理论通过结合粒子轨迹效应近似地提供了拉格朗日描述。通过求解一个非线性常微分方程和一个确定性粒子轨迹方程，可以计算出湍流等离子体中的运行扩散系数。少