论文标题
部分可观测时空混沌系统的无模型预测
Diffusion of relativistic charged particles and field lines in isotropic turbulence: I. Numerical simulations
论文作者
论文摘要
在存在磁性湍流的情况下，非热颗粒在大型磁场上的运输一直是高能天体物理学的一个长期问题。特别令人感兴趣的是并行和垂直均值自由路径的依赖性$λ_ {\ Parallel} $和$λ_{\ perp} $对刚度$ \ MATHCAL {r} $的依赖性。我们重新审视了这一重要问题，以期到从银河宇宙射线运输到天体物理冲击加速的应用。我们已经在合成的，各向同性的kolmogorov湍流中运行了测试粒子模拟，以前所未有的低降低刚度$ \ rg/\ lc/\ lc/\ lc \ simeq 10^{ - 4} $，对应于$ \ simeq 10 \ simeq 10 \ \ simeq 10 \，\ simeq 10 \，\ simeq 10 \，\，\ simeq 10 \，\，\，\，\，\，\，\，\ tert = 4 \，μ\ text {g} $和相关长度$ \ lc = 30 \，\ text {pc} $。提取（渐近）并行和垂直的均值自由路径$λ_ {\ Parallel} $和$λ_ {\ perp} $，我们发现$λ_ {\ parallel} \ propto（\ rg/\ lc/\ lc）相比之下，$λ_ {\ perp} $的依赖性更快，$ \ rg/\ lc $以$ 10^{ - 2} \ sillssim \ rg/\ lc/\ lc \ lysesim 1 $ 1 $ 1 $，但对于$ \ rg/\ rg/\ rg/\ lc/\ lc/\ lc \ ll \ ll \ ll 10^{ - 2} $} （\ rg/\ lc）^{1/3} $。我们的结果对银河宇宙射线的运输具有重要意义。
The transport of non-thermal particles across a large-scale magnetic field in the presence of magnetised turbulence has been a long-standing issue in high-energy astrophysics. Of particular interest is the dependence of the parallel and perpendicular mean free paths $λ_{\parallel}$ and $λ_{\perp}$ on rigidity $\mathcal{R}$. We have revisited this important issue with a view to applications from the transport of Galactic cosmic rays to acceleration at astrophysical shocks. We have run test particle simulations of cosmic ray transport in synthetic, isotropic Kolmogorov turbulence at unprecedentedly low reduced rigidities $\rg/\Lc \simeq 10^{-4}$, corresponding to $\mathcal{R} \simeq 10 \, \text{TV}$ for a turbulent magnetic field of $\Brms = 4 \, μ\text{G}$ and correlation length $\Lc = 30 \, \text{pc}$. Extracting the (asymptotic) parallel and perpendicular mean free paths $λ_{\parallel}$ and $λ_{\perp}$, we have found $λ_{\parallel} \propto (\rg/\Lc)^{1/3}$ as expected for a Kolmogorov turbulence spectrum. In contrast, $λ_{\perp}$ has a faster dependence on $\rg/\Lc$ for $10^{-2} \lesssim \rg/\Lc \lesssim 1$, but for $\rg/\Lc \ll 10^{-2}$, also $λ_{\perp} \propto (\rg/\Lc)^{1/3}$. Our results have important implications for the transport of Galactic cosmic rays.
