Λεπτομέρειες βιβλιογραφικής εγγραφής
| Τίτλος: |
Evolution of NWC Transmitter Wave Power Distribution From the Topside Ionosphere Into the Inner Magnetosphere. |
| Συγγραφείς: |
Xia, Zhiyang1 (AUTHOR) zhiyang.xia@utdallas.edu, Chen, Lunjin1 (AUTHOR), Horne, Richard B.2 (AUTHOR), Miyoshi, Yoshizumi3 (AUTHOR), Kasahara, Yoshiya4 (AUTHOR), Matsuda, Shoya4 (AUTHOR), Shinbori, Atsuki3 (AUTHOR), Hori, Tomoaki3 (AUTHOR), Shinohara, Iku5 (AUTHOR) |
| Πηγή: |
Geophysical Research Letters. 6/16/2026, Vol. 53 Issue 11, p1-9. 9p. |
| Θεματικοί όροι: |
*Radio wave propagation, *Magnetosphere, *Theory of wave motion, *Ray tracing algorithms, *Artificial satellites, *Ionosphere |
| Γεωγραφικοί όροι: |
Northern Hemisphere |
| Περίληψη: |
Ground‐based very low frequency transmitters emit signals that primarily propagate within the Earth–ionosphere waveguide, and some of their energy can propagate into the magnetosphere. Ionospheric observations from the DEMETER satellite reveal a distinct concentric rings pattern of the wave power distribution of the North West Cape transmitter on the transverse (longitude–L‐shell) plane. Using data from the Van Allen Probes and Arase/energization and Radiation in Geospace satellites, we find that the concentric rings pattern is still visible but becomes less distinct. The pattern shifts outward, and becomes more elliptic as the wave propagates from the southern ionosphere to the Northern Hemisphere. To investigate the cause of this evolution, we performed ray tracing simulations under three conditions: ducted propagation, non‐ducted propagation with vertical initial wave normal angles and non‐ducted propagation with spread initial wave normal angles. The results show that non‐ducted propagation with spread wave normal angles best explains the observed evolution of wave power distribution pattern during the propagation. Plain Language Summary: Very low frequency (VLF) radio transmitters on the ground are mainly used for long‐distance communication. Some of the transmitted wave energy can escape upward into near‐Earth space and interact with energetic electrons in the inner magnetosphere. Previous research has mostly focused on how VLF wave power spreads on the meridional plane (over latitude and L‐shell). In this study, we use data from the DEMETER, Van Allen Probes, and Energization and Radiation in Geospace/Arase satellites to examine how waves from the North West Cape transmitter are distributed on the transverse plane (over longitude and L‐shell) and how this distribution evolves during propagation in the inner magnetosphere. The transverse distribution of wave power shows concentric ring‐like patterns near the topside ionosphere, and this pattern moves outward and becomes less distinct as the waves propagate from the Southern Hemisphere to the Northern Hemisphere. By comparing with ray‐tracing simulation results, we show that non‐ducted propagation with broad initial wave normal angles primarily accounts for the observed changes in the wave power distribution. Key Points: The observed North West Cape wave power from Van Allen Probes and Energization and Radiation in Geospace/Arase shows a concentric rings pattern in the magnetosphere, like the ionosphereAs transmitter signals propagate further away from the transmitter, the concentric rings pattern becomes less distinct and moves outwardThe non‐ducted propagation with spread initial wave normal angles can account for the evolution of the wave power distribution [ABSTRACT FROM AUTHOR] |
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