A NEW COSMIC RAY TRANSPORT THEORY IN PARTIALLY TURBULENT SPACE PLASMAS: EXTENDING THE QUASILINEAR APPROACH
A NEW COSMIC RAY TRANSPORT THEORY IN PARTIALLY TURBULENT SPACE PLASMAS: EXTENDING THE QUASILINEAR APPROACH
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DOI：
10.1088/0004-637x/732/2/96
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发表时间：
2011-05
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影响因子：
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通讯作者：
R. Schlickeiser
中科院分区：
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作者：
R. Schlickeiser
提出了一种新的轴对称不可压缩磁湍流磁化空间等离子体中宇宙射线传输理论，将拟线性近似扩展到粒子轨道。允许与均匀磁场中未受扰动的螺旋轨道任意的陀螺相位偏差。对于准稳态和空间均匀的磁湍流，我们推导了小拉莫尔半径近似陀螺相平均宇宙射线福克-普朗克系数。广义福克-普朗克系数正确地减少到相应极限内的已知拟线性值。推导了轴对称湍流中拟线性福克-普朗克系数的新形式，不再涉及贝塞尔函数乘积的无限和，这有助于对指定湍流场相关张量进行数值计算。宇宙线粒子任意相轨道的福克-普朗克系数为垂直和俯仰角福克-普朗克系数提供了严格的上限，这反过来又分别为垂直和平行的空间扩散系数提供了严格的上限和下限，描述了宇宙线相空间密度各向同性部分的空间扩散。对于相关的平均自由程，我们发现对于这种一般情况，最小平行平均自由程与最大垂直平均自由程之和的乘积等于 R2L，其中 RL 表示宇宙射线陀螺半径。
A new transport theory of cosmic rays in magnetized space plasmas with axisymmetric incompressible magnetic turbulence is developed extending the quasilinear approximation to the particle orbit. Arbitrary gyrophase deviations from the unperturbed spiral orbits in the uniform magnetic field are allowed. For quasi-stationary and spatially homogeneous magnetic turbulence, we derive the small Larmor radius approximation gyrophase-averaged cosmic ray Fokker–Planck coefficients. The generalized Fokker–Planck coefficients correctly reduce to their known quasilinear values in the corresponding limit. New forms of the quasilinear Fokker–Planck coefficients in axisymmetric turbulence are derived which no longer involve infinite sums of products of Bessel functions, which facilitate their numerical computation for specified turbulence field correlation tensors. The Fokker–Planck coefficients for arbitrary phase orbits of the cosmic ray particles provide strict upper limits for the perpendicular and pitch-angle Fokker–Planck coefficients, which in turn yield strict upper and lower limits for the perpendicular and parallel spatial diffusion coefficients, respectively, describing the spatial diffusion of the isotropic part of the cosmic ray phase space density. For the associated mean free paths, we find for this general case that the product of the minimum parallel mean free path with the sum of the maximum perpendicular mean free paths equals R2L, where RL denotes the cosmic ray gyroradius.