MODIFICATION OF THE PARALLEL SCATTERING MEAN FREE PATH OF COSMIC RAYS IN THE PRESENCE OF ADIABATIC FOCUSING
MODIFICATION OF THE PARALLEL SCATTERING MEAN FREE PATH OF COSMIC RAYS IN THE PRESENCE OF ADIABATIC FOCUSING
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DOI：
10.1088/0004-637x/792/2/85
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
H.-Q. He;R. Schlickeiser
中科院分区：
文献类型：
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作者：
H.-Q. He;R. Schlickeiser
计算了叠加静磁湍流的大尺度非均匀引导磁场中的宇宙线平均自由程，以澄清文献中一些相互矛盾的结果。从福克-普朗克输运方程导出了一个新的、精确的宇宙射线各向异性积分微分方程。该积分微分方程的摄动分析得出宇宙射线各向异性的解析表达式和宇宙射线分布函数各向同性部分的聚焦输运方程。导出的平行空间扩散系数和相关的宇宙线平均自由程包括绝热聚焦效应，并在均匀引导磁场的限制下简化为标准形式。对于各向同性俯仰角散射的说明性情况，导出的平均自由程与 Beeck & Wibberenz、Bieber & Burger、Kota 和 Litvinenko 的早期表达式一致，但与 Shalchi 的结果不一致。在强绝热聚焦的极限下，与 Shalchi 表达式的分歧尤其强烈。
The cosmic ray mean free path in a large-scale nonuniform guide magnetic field with superposed magnetostatic turbulence is calculated to clarify some conflicting results in the literature. A new, exact integro-differential equation for the cosmic-ray anisotropy is derived from the Fokker–Planck transport equation. A perturbation analysis of this integro-differential equation leads to an analytical expression for the cosmic ray anisotropy and the focused transport equation for the isotropic part of the cosmic ray distribution function. The derived parallel spatial diffusion coefficient and the associated cosmic ray mean free path include the effect of adiabatic focusing and reduce to the standard forms in the limit of a uniform guide magnetic field. For the illustrative case of isotropic pitch angle scattering, the derived mean free path agrees with the earlier expressions of Beeck & Wibberenz, Bieber & Burger, Kota, and Litvinenko, but disagrees with the result of Shalchi. The disagreement with the expression of Shalchi is particularly strong in the limit of strong adiabatic focusing.