Collision-dependent power law scalings in two dimensional gyrokinetic turbulence
Collision-dependent power law scalings in two dimensional gyrokinetic turbulence
复制标题
二维回旋湍流中碰撞相关的幂律缩放
DOI：
10.1063/1.4892347
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发表时间：
2014
影响因子：
2.2
通讯作者：
D. Told
中科院分区：
文献类型：
--
作者：
S. Cerri;A. Navarro;F. Jenko;D. Told
非线性陀螺动力学为描述实验室磁化等离子体和天体物理等离子体中的短波湍流提供了一个合适的框架。在静电极限下，已知该系统在（垂直的）实空间和/或速度空间中表现出向小尺度的自由能级联。自由能的耗散总是由碰撞引起的（不管碰撞有多弱），但可能会在很大范围内扩散。在这里，我们关注亚离子-陀螺半径尺度上的自由衰减二维静电湍流。将已有的弱碰撞极限湍流叶栅标度理论推广到中等碰撞区域。在此背景下，预测了由于多尺度耗散引起的非普适幂律缩放，并通过直接数值模拟证实了这一预测。
Nonlinear gyrokinetics provides a suitable framework to describe short-wavelength turbulence in magnetized laboratory and astrophysical plasmas. In the electrostatic limit, this system is known to exhibit a free energy cascade towards small scales in (perpendicular) real and/or velocity space. The dissipation of free energy is always due to collisions (no matter how weak the collisionality), but may be spread out across a wide range of scales. Here, we focus on freely decaying two dimensional electrostatic turbulence on sub-ion-gyroradius scales. An existing scaling theory for the turbulent cascade in the weakly collisional limit is generalized to the moderately collisional regime. In this context, non-universal power law scalings due to multiscale dissipation are predicted, and this prediction is confirmed by means of direct numerical simulations.
影响因子：
2.2
作者：
I. Abel;Michael Barnes;S. Cowley;W. Dorland;A. Schekochihin
通讯作者：
I. Abel;Michael Barnes;S. Cowley;W. Dorland;A. Schekochihin