Modeling the Two‐Dimensional Propagation of Whistler‐Mode Chorus Waves in the Magnetic Peaks

• Published in: Journal of geophysical research. Space physics 2025-01, Vol.130 (1)
• Main Authors: Feng, Bopu, Yu, Xiongdong, Li, Haimeng, Zhou, Meng, Tang, Rongxin, Ouyang, Zhihai, Xiong, Ying, Yuan, An, Zou, Wenqian, Cheng, Yingqiao
• Format: Article
• Language: English
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2024JA033383

Recent studies have shown that chorus waves can be guided by magnetic peaks based on one‐dimensional theories and simulations. Despite these findings, such ducting propagation within the inner magnetosphere remains unconfirmed. In this research, we conduct detailed ray tracing simulations to explore the two‐dimensional behavior of chorus waves in regions characterized by magnetic peaks. Our findings demonstrate that chorus waves can indeed be guided by magnetic peaks, undergoing repeated reflections on both sides of the peak. Additionally, we discuss the physical mechanisms responsible for these repetitive reflections, offering deeper insights into the process. To further enrich our analysis, we performed a parameter analysis to study how different wave frequencies and initial locations influence the propagation characteristics of chorus waves. The results provide a more comprehensive understanding of how whistler‐mode waves propagate within the magnetosphere, enhancing our knowledge of wave‐particle interactions and the dynamics of space plasma environments. Whistler‐mode chorus waves can propagate in either ducted or non‐ducted modes, depending on the gradient of spatial mediums such as plasma density or magnetic field strength. While the characteristics of propagation in density ducts are well understood, propagation through magnetic peak ducts may be more complex. In this study, two‐dimensional ray tracing simulations are performed, our results show that rays can indeed be guided by magnetic peaks, exhibiting repetitive reflections within them. However, when considering Landau damping the presence of the magnetic duct can restrict most waves, only those waves launched near the center may propagate to higher latitudes, particularly for upper band waves. We also investigate the differences between ducts of two different sizes. These findings provide new insights into the propagation of whistler‐mode waves within the magnetosphere. Two‐dimensional ducting propagation of chorus waves in magnetic peaks is investigated through ray tracing simulations Magnetic duct can guide chorus waves through repetitive reflections but also prevents most waves from propagating to higher latitudes The repetitive reflections along the wave propagation path are explained through a simple theoretical analysis