标题： 超新星冲击波中宇宙射线弹道冲浪加速的重新解释 显示英文标题

标题： Reinterpretation of the Fermi acceleration of cosmic rays in terms of the ballistic surfing acceleration in supernova shocks

摘要： 利用地球弓激波多尺度磁层任务近期关于冲击加速机制的研究成果，重新审视了低阶Fermi加速在解释宇宙射线能谱方面的适用性。 研究显示，Fermi机制是对弹道冲浪加速（BSA）机制的粗略近似。 尽管两种机制在粒子遭遇冲击一次后获得的能量表达式相似，从而导致宇宙射线能量谱的幂律分布类似，但发现Fermi机制与电动力学的基本方程不一致。 研究表明，宇宙射线的能谱指数由平均磁场压缩而非密度压缩决定，这与Fermi模型不同。 研究指出，在5×10^{15} eV能量处观测到的膝部可能对应于与超新星遗迹中冲击波大小相当的离子。 BSA机制可以准确再现膝部以下能量s = -2.5的观测能谱指数，以及膝部以上能量s = -3的更陡峭的能谱。 根据BSA推断，达到膝部的加速时间约为300年。 低阶Fermi加速并不代表一个物理上有效的机制，在与空间中准垂直冲击相关的应用或模型中应被弹道冲浪加速取代。 值得注意的是，先前误归因于冲击漂移加速（SDA）的BSA机制实际上是在冲击外部运行，而SDA是在冲击内部运行。 显示英文摘要

摘要： The applicability of first-order Fermi acceleration in explaining the cosmic ray spectrum has been reexamined using recent results on shock acceleration mechanisms from the Multiscale Magnetospheric mission in Earth's bow shock. It is demonstrated that the Fermi mechanism is a crude approximation of the ballistic surfing acceleration (BSA) mechanism. While both mechanisms yield similar expressions for the energy gain of a particle after encountering a shock once, leading to similar power-law distributions of the cosmic ray energy spectrum, the Fermi mechanism is found to be inconsistent with fundamental equations of electrodynamics. It is shown that the spectral index of cosmic rays is determined by the average magnetic field compression rather than the density compression, as in the Fermi model. It is shown that the knee observed in the spectrum at an energy of 5x10^{15} eV could correspond to ions with a gyroradius comparable to the size of shocks in supernova remnants. The BSA mechanism can accurately reproduce the observed spectral index s = -2.5 below the knee energy, as well as a steeper spectrum, s = -3, above the knee. The acceleration time up to the knee, as implied by BSA, is on the order of 300 years. First-order Fermi acceleration does not represent a physically valid mechanism and should be replaced by ballistic surfing acceleration in applications or models related to quasi-perpendicular shocks in space. It is noted that BSA, which operates outside of shocks, was previously misattributed to shock drift acceleration (SDA), which operates within shocks.