Ion cyclotron resonance is one of the fundamental energy conversion processes through field-particle interaction in collisionless plasmas. However, the key evidence for ion cyclotron resonance (i.e., the coherence between electromagnetic fields and the ion phase space density) and the resulting damping of ion cyclotron waves (ICWs) has not yet been directly observed. Investigating the high-quality measurements of space plasmas by the Magnetospheric Multiscale (MMS) satellites, we find that both the wave electromagnetic field vectors and the bulk velocity of the disturbed ion velocity distribution rotate around the background magnetic field. Moreover, we find that the absolute gyro-phase angle difference between the center of the fluctuations in the ion velocity distribution functions and the wave electric field vectors falls in the range of (0, 90) degrees, consistent with the ongoing energy conversion from wave-fields to particles. By invoking plasma kinetic theory, we demonstrate that the field-particle correlation for the damping ion cyclotron waves in our theoretical model matches well with our observations. Furthermore, the wave electric field vectors ($δ\mathbf{E'}_{\mathrm {wave,\perp}}$), the ion current density ($δ\mathbf{J}_\mathrm {i,\perp}$) and the energy transfer rate ($δ\mathbf{J}_\mathrm {i,\perp}\cdot δ\mathbf{E'}_{\mathrm {wave,\perp}}$) exhibit quasi-periodic oscillations, and the integrated work done by the electromagnetic field on the ions are positive, indicates that ions are mainly energized by the perpendicular component of the electric field via cyclotron resonance. Therefore, our combined analysis of MMS observations and kinetic theory provides direct, thorough, and comprehensive evidence for ICW damping in space plasmas.
Wave Emission and Absorption in a Near-Sun Proton-Cyclotron Wave Storm
University of Arizona（亚利桑那大学）；University College London（伦敦大学学院）；University of California, Berkeley（加州大学伯克利分校）；Smithsonian Astrophysical Observatory（史密森尼天体物理台）
Analytic stability boundaries for compressional and global Alfvén eigenmodes driven by fast ions. I. Interaction via ordinary and anomalous cyclotron resonances
Influence of wave frequency variation on anomalous cyclotron resonance interaction of energetic electrons with finite amplitutude ducted whistler-mode wave
Three Dimensional Multiphysics Modelling of Helicon Wave Heating and Antenna Plasma Coupling for Boundary Density Control in Toroidal Fusion Plasmas
Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences（中国科学院合肥物质科学研究院等离子体物理研究所）；Science Island Branch of Graduate, University of Science and Technology of China（中国科学技术大学研究生院科学岛分院）；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）；Mathematical Sciences Institute, Australian National University（澳大利亚国立大学数学科学学院）；Department of Mathematics and Physics, University of South China（南华大学数学与物理学院）；School of Physical and Mathematical Sciences, Nanyang Technological University（南洋理工大学物理与数学学院）；College of Physics and Optoelectronic Engineering, Shenzhen University（深圳大学物理与光电工程学院）
Non-thermal electron cyclotron emission during runaway plateau in tokamak disruptions from a highly anisotropic dielectric tensor
Seoul National University（首尔大学）；Nuclear Research Institute for Future Technology and Policy, Seoul National University（首尔大学未来技术与政策核研究所）；POSTECH（浦项工科大学）
