论文标题
二维无碰撞磁重新连接中的相对论非热粒子加速度
Relativistic Nonthermal Particle Acceleration in Two-Dimensional Collisionless Magnetic Reconnection
论文作者
论文摘要
磁重新连接，尤其是在相对论方案中，为加速相对论颗粒提供了有效的机制，因此为来自各种天体物理学来源的非热高能发射提供了有吸引力的物理解释。我提出了一个简单的分析模型，该模型阐明了负责重新连接驱动的相关性非热粒子加速度（NTPA）的关键物理过程，该模型在两个维度的大型系统，浆液为主导的方向上。该模型旨在解释幂律指数$ p $的数值观察依赖项和高能截止$γ_c$ $γ_c$的环境等离子磁力磁盘上的非热粒子能谱$ f（γ）$σ$，以及（用于$γ_C$）的系统尺寸size size size size $ l $ l $。在这个自相似模型中，能量颗粒被平面外重新连接电场$ e _ {\ rm rec} $连续加速，直到它们被重新连接的磁场磁化并最终被捕获在足够大以隔离它们的浆样中。该模型还包括通过快速移动的浆液弹出粒子的扩散加速度。我认为，电加速器和磁化之间的平衡控制着幂律指数，而陷入浆液中的截止值则控制着截止，从而将颗粒的能量谱与浆液分布联系起来。
Magnetic reconnection, especially in the relativistic regime, provides an efficient mechanism for accelerating relativistic particles and thus offers an attractive physical explanation for nonthermal high-energy emission from various astrophysical sources. I present a simple analytical model that elucidates key physical processes responsible for reconnection-driven relativistic nonthermal particle acceleration (NTPA) in the large-system, plasmoid-dominated regime in two dimensions. The model aims to explain the numerically-observed dependencies of the power-law index $p$ and high-energy cutoff $γ_c$ of the resulting nonthermal particle energy spectrum $f(γ)$ on the ambient plasma magnetization $σ$, and (for $γ_c$) on the system size $L$. In this self-similar model, energetic particles are continuously accelerated by the out-of-plane reconnection electric field $E_{\rm rec}$ until they become magnetized by the reconnected magnetic field and eventually trapped in plasmoids large enough to confine them. The model also includes diffusive Fermi acceleration by particle bouncing off rapidly moving plasmoids. I argue that the balance between electric acceleration and magnetization controls the power-law index, while trapping in plasmoids governs the cutoff, thus tying the particle energy spectrum to the plasmoid distribution.
