Velocity-space compression from Fermi acceleration with Lorentz scattering
Velocity-space compression from Fermi acceleration with Lorentz scattering
复制标题
洛伦兹散射费米加速的速度空间压缩
DOI：
10.1103/physreve.105.015207
复制
发表时间：
2022
影响因子：
2.4
通讯作者：
Fisch, N. J.
中科院分区：
文献类型：
--
作者：
Waybright, J. C.;Mlodik, M. E.;Fisch, N. J.
费米加速模型描述了宇宙射线粒子如何通过与移动磁场相互作用而加速到极高的速度。我们确定了模型的一种变体，其中轻离子与移动壁相互作用，同时由于存在较重的离子物质而通过库仑碰撞经历俯仰角散射。碰撞引入了随机分量，这增加了粒子加速曲线的复杂性，并将其与无碰撞费米加速模型区分开来。费米加速度的这种简化变化所捕获的不寻常效应是相空间的不守恒，最初能量单调递减的粒子分布有可能在压缩时表现出能量峰值。峰值能量分布可能有有趣的应用，例如优化聚变反应性或表征表现出非热特征的天体物理现象。
The Fermi acceleration model describes how cosmic ray particles accelerate to great speeds by interacting with moving magnetic fields. We identify a variation of the model where light ions interact with a moving wall while undergoing pitch angle scattering through Coulomb collisions due to the presence of a heavier ionic species. The collisions introduce a stochastic component which adds complexity to the particle acceleration profile and sets it apart from collisionless Fermi acceleration models. The unusual effect captured by this simplified variation of Fermi acceleration is the nonconservation of phase space, with the possibility for a distribution of particles initially monotonically decreasing in energy to exhibit an energy peak upon compression. A peaked energy distribution might have interesting applications, such as to optimize fusion reactivity or to characterize astrophysical phenomena that exhibit nonthermal features.