Bibliographic Details
| Title: |
The Wave Normal Angle Characteristic of Whistler‐Mode Waves in the Dayside Terrestrial Space Based on MMS Observations. |
| Authors: |
Zhang, H.1,2,3,4,5 (AUTHOR), Lu, J. Y.2,3 (AUTHOR) jylu@nuist.edu.cn, Zhong, Z. H.6 (AUTHOR), Feng, B. P.6 (AUTHOR), Wang, M.2,3 (AUTHOR), Tang, R. X.6 (AUTHOR), Deng, X. H.6 (AUTHOR) |
| Source: |
Journal of Geophysical Research. Space Physics. Apr2025, Vol. 130 Issue 4, p1-16. 16p. |
| Subject Terms: |
Dynamic pressure, Wind pressure, Magnetopause, Magnetosphere, Particle interactions |
| Abstract: |
Wave normal angle (WNA) is an important parameter in the analysis of wave‐particle interactions. The WNA distribution may significantly influence the effective interaction between the waves and solar wind electrons. As a region of direct interaction with the solar wind, the WNA distribution of whistler‐mode waves in the dayside terrestrial space is still unclear. This paper reports statistical work on the WNA distribution of whistler‐mode waves in the dayside terrestrial region. The results show that whistler‐mode waves with quasi‐parallel WNA (θ<35°) $(\theta < 35{}^{\circ})$ tend to increase gradually near the magnetopause, while the occurrence rate of oblique waves (θ≥35°) $(\theta \ge 35{}^{\circ})$ increases significantly in the magnetosheath with increasing solar wind dynamic pressure Psw $\left({P}_{sw}\right)$. Under the strong Psw ${P}_{sw}$ condition, the distribution of WNAs both in quasi‐parallel and oblique decreases sharply within the 0.5–0.8 fce ${f}_{ce}$ frequency range. Moreover, we find that strong Psw ${P}_{sw}$ can effectively affect the amplitude of oblique whistler‐mode waves. These results can improve understanding of the kinetic process associated with whistler‐mode waves. Plain Language Summary: Whistler‐mode waves are commonly observed in the Earth's and planetary magnetosphere and magnetosheath. The Wave normal angles (WNAs) of whistler‐mode waves are crucial for analyzing wave‐particle interactions in space. While the WNA distribution of whistler‐mode waves has been extensively studied in the inner magnetosphere, its detailed characterization in the dayside terrestrial region remains unclear. In this study, We have statistically studied the wave normal angle distribution of whistler‐mode waves in the dayside terrestrial space and their dependence on Psw ${P}_{sw}$ based on Magnetospheric Multiscale data. We find that whistler‐mode waves with smaller WNAs (quasi‐parallel) tend to occur in the magnetosphere, while waves with larger WNAs (oblique) have a significant response in the magnetosheath as the Psw ${P}_{sw}$ increases. Under strong Psw ${P}_{sw}$, the range of these angles decreases sharply within 0.5–0.8 fce ${f}_{ce}$ frequency ranges, and this pressure can significantly impact the amplitude of oblique whistler‐mode waves. These findings provide a comprehensive understanding of the processes associated with whistler‐mode waves and their interactions with particles. Key Points: As Psw increases, quasi‐parallel waves occur more often near the magnetopause, oblique waves increase significantly in the magnetosheathUnder strong Psw, the WNA distribution of both quasi‐parallel and oblique waves decreases sharply within the 0.5–0.8 fce frequency rangeThe strong Psw can significantly affect the amplitude of oblique whistler‐mode waves [ABSTRACT FROM AUTHOR] |
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| Database: |
GreenFILE |
