Spectral analyses of energetic particle (EP) driven bursts of MHD fluctuations in magnetically confined plasmas often exhibit multiple simultaneous chirps. While the superposition of oscillations at multiple frequencies necessarily causes beating in the signal acquired by a localized external probe, self-consistent hybrid simulations of chirping EP modes in a JT-60U tokamak plasma have demonstrated the possibility of global beating, where the electromagnetic field vanishes globally between beats and reappears with opposite phase. This implies that there can be a single field mode that oscillates at multiple frequencies simultaneously when resonantly driven by multiple density waves in EP phase space. Conversely, this means that the EP density waves are mutually coupled and interfere with each other via the jointly driven field, a mechanism ignored in some theories. In this treatise, we study the role of field pulsations in general and beating in particular using the Hamiltonian guiding center orbit-following code ORBIT with a reduced wave-particle interaction model in realistic geometry. Through amplitude pulsations and phase jumps, beating is found to drive the evolution of EP phase space structures. Observations: (1) Beating causes density wave fronts to advance radially in pulses. The resulting chirps become staircase-like. (2) The beats facilitate convective transfer of material between neighboring layers of phase space density waves. On the one hand, this may delay detachment of solitary vortices. On the other hand, it facilitates the accumulation of hole and clump fragments into larger structures. (3) Long-range chirping occurs when massive holes or clumps detach and drift away from the turbulent belt around the seed resonance. The detached vortices can remain robust and, on average, maintain their concentric nested layers while being perturbed by the field's continued beating.
Frequency Chirping of Energetic-Particle-Driven Geodesic Acoustic Modes in Tokamaks
De Vinci Higher Education, De Vinci Research Center（德芬奇高等教育中心，德芬奇研究中心）；Center for Nonlinear Plasma Science and C.R. ENEA Frascati（非线性等离子体科学中心与ENEA弗拉斯卡蒂研究中心）；Max Planck Institute for Plasma Physics（马克斯·普朗克等离子体物理研究所）
Study of the likelihood of Alfvénic mode bifurcation in NSTX and predictions for ITER baseline scenarios
在NSTX中发现了固定频率和啁啾相位之间的罕见Alfvénic波跃迁，通常观察到Alfvénic波表现出啁啾或雪崩响应。对于这些跃迁，我们应用一个标准[Duarte et al，Nucl.Fusion 57，054001（2017）]来预测托卡马克中快速离子再分布的性质处于对流或扩散非线性状态。对于NSTX放电中的过渡是不伴随着在束沉积功率或修改注入的射频功率的变化，它已被发现，异常的快速离子传输是固定频率模式的行为和快速啁啾之间的分叉可能的调解人。为了定量评估，使用GTS代码进行了静电离子温度梯度湍流和捕获电子模式湍流对啁啾的影响的全局陀螺动力学模拟。调查扩展的Alfvénic本征模式的基线ITER的情况下，包括榆树，先进的和混合的情况下，通过可能的光谱行为的预测研究。已经观察到，大多数模式被发现是稳定和啁啾相位之间的边界。
Fully nonlinear phenomenology of the bump-on-tail (BOT) instability with drag, diffusion and Krook relaxation
Fundamental Plasma Physics and Innovative Applications Laboratory, School of Electrical Engineering, Chongqing University（重庆大学电气工程学院基础等离子体物理与创新应用实验室）；Institute of Nuclear Energy and Technology Innovation, Chongqing University（重庆大学核能技术创新研究院）；School of Physical and Mathematical Sciences, Nanyang Technological University（南洋理工大学物理与数学学院）；Physical Electronics Department, Faculty of Physics, Lomonosov Moscow State University（莫斯科国立大学物理系物理电子学系）；Department of Advanced Environmental Science and Engineering, Kyushu University（九州大学先进环境科学与工程系）；Applied Physics lab for PLasma Engineering (APPLE), Department of Physics, Chungnam National University（忠南国立大学物理系等离子体工程应用物理实验室）
On How Zonal Fields Suppress Reversed Shear Alfvén Eigenmode in Tokamak Plasmas
Southwestern Institute of Physics（西南核物理与化学研究所）；Center for Nonlinear Plasma Science and C.R. ENEA Frascati（非线性等离子体科学中心及ENEA弗拉斯卡蒂研究中心）；Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；Institute for Fusion Theory and Simulation and School of Physics, Zhejiang University（浙江大学物理学院聚变理论与模拟研究所）；Institute of Plasma Physics, Chinese Academy of Sciences（中国科学院等离子体物理研究所）
Long lasting plasma density structures utilizing tailored density profiles
Chalmers University of Technology（查尔姆斯理工大学）；University of Oxford（牛津大学）；Sorbonne Université, CNRS, École Polytechnique, CEA（索邦大学、法国国家科学研究中心、巴黎综合理工学院、法国原子能和替代能源委员会）；Zhejiang University（浙江大学）；University of California, Berkeley（加州大学伯克利分校）
Nonlinear evolution of the plasma beatwave: Compressing the laser beatnotes via electromagnetic cascading
电子等离子体波（EPW）的近共振拍频波激发可以在稀薄等离子体中产生飞秒电磁脉冲。EPW产生共同移动的折射率光栅，其在差频处引起激光相位调制。相位调制激光器的带宽与等离子体长度、激光波长和电子密度扰动幅度的乘积成比例。激光光谱由红色和蓝色边带的级联组成，这些边带的位移是拍频的整数倍。当拍频低于电子等离子体频率时，在每个激光拍音的中心附近，红移的光谱分量相对于蓝移的光谱分量在时间上提前。等离子体的群速度色散将如此啁啾的拍音压缩到几个激光周期的持续时间，从而产生具有拍频周期性的尖锐EM尖峰的训练。根据等离子体和激光器的参数，啁啾和压缩可以同时在同一个等离子体中实现，也可以在不同的等离子体中顺序实现。在弱相对论近似下，描述了激光拍频波末端电子密度扰动的时间和一维空间演化。利用压缩效应，我们证明了EPW激发[G。Shvets，Phys. Rev. Lett. 93，195004（2004）]可以用初始亚阈值拍频波脉冲来实现。
