Linearized model Fokker-Planck collision operators for gyrokinetic simulations. I. Theory
Linearized model Fokker-Planck collision operators for gyrokinetic simulations. I. Theory
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DOI：
10.1063/1.3046067
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发表时间：
2008-08
影响因子：
2.2
通讯作者：
I. Abel;Michael Barnes;S. Cowley;W. Dorland;A. Schekochihin
中科院分区：
文献类型：
--
作者：
I. Abel;Michael Barnes;S. Cowley;W. Dorland;A. Schekochihin
一个新的解析和数值管理模型碰撞算子是专门为湍流模拟。类粒子碰撞算子包括俯仰角散射和能量扩散，满足碰撞算子所需的物理约束：它保持粒子、动量和能量守恒，遵守玻尔兹曼H定理（碰撞不能减少熵），在麦克斯韦方程组上消失，并有效地消散速度空间中的小尺度结构。详细介绍了将该碰撞算子转换为陀螺平均形式以用于陀螺动力学模拟的过程。陀螺平均模型运营商示出在相空间中的小尺度比以前建议的模型有更合适的行为。电子-离子和离子-电子碰撞的模型运营商。
A new analytically and numerically manageable model collision operator is developed specifically for turbulence simulations. The like-particle collision operator includes both pitch-angle scattering and energy diffusion and satisfies the physical constraints required for collision operators: it conserves particles, momentum, and energy, obeys Boltzmann’s H-theorem (collisions cannot decrease entropy), vanishes on a Maxwellian, and efficiently dissipates small-scale structure in the velocity space. The process of transforming this collision operator into the gyroaveraged form for use in gyrokinetic simulations is detailed. The gyroaveraged model operator is shown to have more suitable behavior at small scales in phase space than previously suggested models. Model operators for electron-ion and ion-electron collisions are also presented.