非线性阿尔文波中的混沌宇宙线加速
Chaotic cosmic ray acceleration in nonlinear Alfven waves
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中文总结 AI 辅助
该研究发现，当线偏振阿尔文波相对振幅≥0.25时粒子运动混沌，近共振阿尔文波可模拟经典散射，其非扩散特性能避免90°势垒并提高特殊粒子加速率。
中文摘要 AI 辅助
我们证明，粒子在相对振幅δ=B_w/B_0≳0.25的单相干线偏振（LP）阿尔文波中的运动变为混沌。因此，足够强的近共振阿尔文波（r_L k_∥~1，其中r_L为相对论回旋半径，k_∥为波矢）可导致瞬态捕获和相位混合，模拟经典散射。通过阿尔文混沌的俯仰角演化是非扩散的——被捕获轨迹上的粒子可在一次散射事件中反转速度，这既避免了90°势垒问题，又提高了特殊粒子的加速率。
英文摘要
We demonstrate that motion of a particle in a single coherent linearly polarized (LP) Alfven wave with relative amplitude $δ= B_w /B_0 \gtrsim 0.25 $ becomes chaotic. As a result, a sufficiently strong, near resonant Alfven waves ($r_L k_\parallel \sim 1$, $r_L $ is relativistic cyclotron radius, $k_\parallel$ is wavevector) can lead to transient trapping and phase mixing, imitating classical scattering. Evolution of pitch angle via Alfven chaos is non-diffusive - a particle on trapped trajectory can reverse its velocity in one scattering event. This both avoids the problem of the 90$^\circ$ barrier, and increases the acceleration rate for those special particle.
