自激发波对逃逸电子的控制

中文摘要 AI 辅助

托卡马克等离子体中的逃逸电子雪崩可受到由非麦克斯韦逃逸分布驱动的动力学不稳定性限制。我们构建了一个准稳态的约化模型，其中总等离子体电流和体电子温度是给定的，而感应电场则根据欧姆体电流与逃逸电子电流之间的分配自洽地确定。由于波增长时间远短于电流衰减时间，我们考虑边缘稳定状态，在该状态下，逃逸电子驱动的哨声波激发与碰撞阻尼相平衡。由此产生的状态分为三个区域：无雪崩的亚临界欧姆区、逃逸增长将感应电场松弛至雪崩阈值的雪崩区，以及自激发哨声波增强动量空间扩散并限制逃逸电流的不稳定性调控区。在不稳定性调控区，哨声波谱形成窄脊，低能逃逸电子承载大部分逃逸电流。

英文摘要

Runaway-electron avalanches in tokamak plasmas can be limited by kinetic instabilities driven by the non-Maxwellian runaway distribution. We formulate a reduced model for the quasi-steady state in which the total plasma current and bulk electron temperature are prescribed, while the inductive electric field is determined self-consistently from the partition between Ohmic bulk current and runaway-electron current. Because the wave growth time is short compared with the current-decay time, we consider a marginal-stability regime, in which whistler-wave drive by the runaway electrons balances collisional damping. The resulting states separate into three regimes: a subcritical Ohmic regime without an avalanche, an avalanche regime in which runaway growth relaxes the inductive field to the avalanche threshold, and an instability-regulated regime in which self-excited whistler waves enhance momentum-space diffusion and limit the runaway current. In the instability-regulated regime, the whistler wave spectrum forms a narrow ridge, and low-energy runaway electrons carry most of the runaway current.

发表机构

• Virginia Polytechnic Institute and State University（弗吉尼亚理工大学）
• The University of Texas at Austin（德克萨斯大学奥斯汀分校）

机构由 AI 辅助整理，请以论文原文为准。