Scattering of energetic particles by anisotropic magnetohydrodynamic turbulence with a goldreich-sridhar power spectrum
Scattering of energetic particles by anisotropic magnetohydrodynamic turbulence with a goldreich-sridhar power spectrum
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DOI：
10.1103/physrevlett.85.4656
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发表时间：
2000-08
影响因子：
8.6
通讯作者：
Chandran
中科院分区：
文献类型：
--
作者：
Chandran
在准线性近似下计算了各向异性、不可压缩、磁流体动力学湍流的Goldreich-Sridhar（GS）谱的散射率。由于小尺度波动被限制在波矢几乎垂直于背景磁场，散射太弱，既不能提供银河宇宙线传播模型中常用的平均自由路径，也不能提供在准平行冲击下宇宙线加速所需的平均自由路径。在强烈的俯仰角散射发生的地方，这是由于GS光谱所描述的波动，例如流动的宇宙射线产生的波动。
Scattering rates for a Goldreich-Sridhar (GS) spectrum of anisotropic, incompressible, magnetohydrodynamic turbulence are calculated in the quasilinear approximation. Because the small-scale fluctuations are constrained to have wave vectors nearly perpendicular to the background magnetic field, scattering is too weak to provide either the mean-free paths commonly used in Galactic cosmic-ray propagation models or the mean-free paths required for acceleration of cosmic rays at quasiparallel shocks. Where strong pitch-angle scattering occurs, it is due to fluctuations not described by the GS spectrum, such as fluctuations generated by streaming cosmic rays.