AI 中文总结
研究遍历磁几何中逃逸电子输运，传统扩散模型有局限。基于混沌理论提出新模型，超越Rechester - Rosenbluth近似，考虑粘性区域影响，在Ullmann - Caldas图和JET模拟中适用性良好，拟合效果显著。
AI 中文摘要
在遍历磁几何中逃逸电子（RE）的输运是一个活跃的研究领域。通过直接模拟粒子轨迹来计算输运在计算上成本高昂。因此常采用扩散模型，如Rechester和Rosenbluth提出的模型，将输运效应纳入简化模拟。但基于扩散的模拟与直接模拟的比较表明，输运通常并非纯粹扩散性的。本文引入了一个基于混沌理论的简单输运模型，超越了Rechester - Rosenbluth近似。除了混沌扩散，该模型还考虑了所谓粘性区域的影响，即磁岛周围的捕获层，粒子逃逸在此减缓为幂律衰减而非指数衰减。我们在对应TBR - 1托卡马克参数的Ullmann - Caldas图以及JET破裂场景的JOREK模拟中展示了该模型的适用性，在两种情况下都取得了显著良好的拟合效果。
英文摘要
The transport of runaway electrons (RE) in ergodic magnetic geometries is an area of active study. Computing the transport from the direct simulation of particle trajectories is computationally expensive. Instead, diffusion models, such as the one by Rechester and Rosenbluth, are often employed to incorporate transport effects into reduced simulations. However, the comparison of diffusion-based to direct simulations reveals that the transport is typically not purely diffusive. In this paper, we introduce a simple transport model, based on chaos theory, which goes beyond the Rechester-Rosenbluth approximation. Besides chaotic diffusion, our model takes into account the effect of so-called sticky regions, a trapping layer around magnetic islands, where particle escape slows down to a power-law decay rather than an exponential decay. We demonstrate the applicability of the model both in the Ullmann-Caldas map with parameters corresponding to the TBR-1 tokamak, and in a JOREK simulation of a JET disruption scenario, with remarkably good fits achieved in both cases.
