论文标题

使用相空间水袋的chiring波的理论描述

Theoretical description of chirping waves using phase-space waterbags

论文作者

Hezaveh, Hooman, Qu, Zhisong, Hole, Matthew, Dewar, Robert

论文摘要

快速粒子的指导中心动力学可以改变频率的能量粒子驱动模式的行为。在本文中,较早的被困/通过基因座模型的适用性[H. Hezaveh等人2017 NUCL。融合57 126010]已扩展到波浪陷阱区域可以扩展和捕获环境颗粒的机制。该扩展允许研究在整个能量粒子轨道范围内向上和向下频率chi的波浪。在绝热近似下,通过拉格朗日轮廓方法分析了能量颗粒的相位空间,在该方法中,使用相空间水袋将岛屿离散。为了解决相位空间岛的快速形成过程中的动态并找到适当的初始化,使用Bump-on-Tail(BOT)代码实现全尺度建模。除了研究单个共振中具有加深电势的chir波的演变外,我们还选择了特定的音调角范围,其中较高的共振可以对波粒子相互作用产生相对相当大的贡献。因此,该模型还可以在双回声方案中求解,在其中我们报告了由于$ 2^{\ text {nd}} $共振而对chirawing波的行为进行了重大修改。本文介绍的模型给出了在实验中观察到的远程频率chi频信号的综合1D范式,并具有向上和向下chi的频率和多个共振。

The guiding centre dynamics of fast particles can alter the behaviour of energetic particle driven modes with chirping frequencies. In this paper, the applicability of an earlier trapped/passing locus model [H. Hezaveh et al 2017 Nucl. Fusion 57 126010] has been extended to regimes where the wave trapping region can expand and trap ambient particles. This extension allows the study of waves with up-ward and down-ward frequency chirping across the full range of energetic particle orbits. Under the adiabatic approximation, the phase-space of energetic particles is analysed by a Lagrangian contour approach where the islands are discretised using phase-space waterbags. In order to resolve the dynamics during the fast formation of phase-space islands and find an appropriate initialisation for the system, full-scale modelling is implemented using the bump-on-tail (BOT) code. In addition to investigating the evolution of chirping waves with deepening potentials in a single resonance, we choose specific pitch-angle ranges in which higher resonances can have a relatively considerable contribution to the wave-particle interaction. Hence, the model is also solved in a double-resonance scenario where we report on the significant modifications to the behaviour of the chirping waves due to the $2^{\text{nd}}$ resonance. The model presented in this paper gives a comprehensive 1D paradigm of long range frequency chirping signals observed in experiments with both up-ward and down-ward chirping and multiple resonances.

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