On push-forward representations in the standard gyrokinetic model
On push-forward representations in the standard gyrokinetic model
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DOI：
10.1063/1.4905705
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发表时间：
2015-01
影响因子：
2.2
通讯作者：
N. Miyato;M. Yagi;B. Scott
中科院分区：
文献类型：
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作者：
N. Miyato;M. Yagi;B. Scott
两种表示的流体力矩的陀螺中心分布函数和陀螺中心坐标，这是所谓的推进表示，在标准的静电gyrokinetic模型进行比较。在传统上用于推导陀螺运动泊松方程的表示中，陀螺中心分布函数的拉回变换包含陀螺中心变换的影响，因此包含静电势波动的影响，这由分布函数和产生陀螺中心变换的标量函数之间的泊松括号来描述。通常，只考虑一阶母函数的最低阶解来显式导出陀螺动力学泊松方程。这是真实的，在明确推导表示标量流体的时刻与极化条款。人们也恢复粒子的抗磁通量在这个顺序，因为它是与引导中心变换。然而，高阶的解决方案，需要从传统的表示，以获得有限的拉莫尔半径项的粒子通量，包括偏振漂移通量。另一方面，最低阶的解决方案是足够的另一种表示，其中陀螺中心变换部分与引导中心的一个相结合，并没有出现拉回变换的分布函数。
Two representations of fluid moments in terms of a gyro-center distribution function and gyro-center coordinates, which are called push-forward representations, are compared in the standard electrostatic gyrokinetic model. In the representation conventionally used to derive the gyrokinetic Poisson equation, the pull-back transformation of the gyro-center distribution function contains effects of the gyro-center transformation and therefore electrostatic potential fluctuations, which is described by the Poisson brackets between the distribution function and scalar functions generating the gyro-center transformation. Usually, only the lowest order solution of the generating function at first order is considered to explicitly derive the gyrokinetic Poisson equation. This is true in explicitly deriving representations of scalar fluid moments with polarization terms. One also recovers the particle diamagnetic flux at this order because it is associated with the guiding-center transformation. However, higher-order solutions are needed to derive finite Larmor radius terms of particle flux including the polarization drift flux from the conventional representation. On the other hand, the lowest order solution is sufficient for the other representation, in which the gyro-center transformation part is combined with the guiding-center one and the pull-back transformation of the distribution function does not appear.