A Large‐Scale Magnetospheric Line Radiation Event in the Upper Ionosphere Recorded by the China‐Seismo‐Electromagnetic Satellite

Hu, Yunpeng; Zhima, Zeren; Fu, H. S.; Cao, Jinbin; Piersanti, Mirko; Wang, Tieyan; Yang, Dehe; Sun, Xiyan; Lv, Fangxian; Chen, Lu; Wang, Qiao; Wang, Yalu; Shen, Xuhui

doi:10.1029/2022ja030743

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…The wave propagation parameters such as the wave vector, and the wave polar and azimuthal angles are defined under a Magnetic Field Aligned Coordinate (MFAC) system (Santolik and Gurnett, 2003). As shown in Figure 1, we define the Z-axis points along with the background magnetic field B 0 , the Y-axis is directed along the cross product of the Z-axis and the position vector of the satellite (so that the +Y-axis is nominally eastward at the equator), and the X-axis completes a right-handed system (Hu et al, 2023) under the MFAC system. According to the SVD algorithm, we can use two angles to define the relationship between the wave vector k and the background magnetic field B 0 , one is the polar angle θ k , and the other is the azimuthal angle φ k .…”

Section: Figurementioning

confidence: 99%

“…According to the SVD algorithm, we can use two angles to define the relationship between the wave vector k and the background magnetic field B 0 , one is the polar angle θ k , and the other is the azimuthal angle φ k . We can determine whether the wave vector is parallel or perpendicular to the ambient magnetic field B 0 by the wave normal angles θ k (0 -90); and determine the wave propagates towards the decreasing L shell direction in the meridian plane by the values of φk (±180 °), Figure 4 or propates to the local magnetic meridian plane (φk = 90 °) (Hu et al, 2023).…”

Section: Figurementioning

confidence: 99%

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The upward propagating ionospheric hiss waves during the seismic time observed by the China seismo-electromagnetic satellite

Lv¹,

Zhima³

et al. 2023

Front. Astron. Space Sci.

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The ionospheric hiss wave is a broadband incoherent and structureless electromagnetic emission. They appear in a relatively narrower frequency range between −0.1 and 1.5 kHz. However, according to previous observations, abnormal electromagnetic emissions during seismic activities also preferentially appear in the same frequency range of ionospheric hiss. This work studies the propagation features of the ionospheric hiss during seismic time based on the observations from the CSES (China Seismo-Electromagnetic Satellite). The wave vector analysis shows that during seismic activities, except for the downward propagating ionospheric hiss which is a common phenomenon in the ionosphere, there are upward propagating emissions mixed with the downward propagating ionospheric hiss. We made a statistical analysis of the shallow strong earthquakes (M ≥ 6.0, depth below 30 km) that occurred in mainland China from 2019 to 2022. We selected the ionospheric hiss events recorded by orbits passing over the epicenters within a time window (the 1-month prior to and 1-week after the main shock). We found that although most of the events are the typical downward propagating ionospheric hiss waves, however, there are certain events mixed with the upward propagating emissions. The statistical distribution analysis of wave propagation parameters shows that the major part of wave normal angles vary from 40 to 60, the azimuthal angles predominately attain below 40, and the ellipticity shows a more complicated feature varying around ± 0.5, and the planarity values predominate at values between 0.6 and 1. The frequency band of the upward propagating ionospheric hiss mostly varies between 300 Hz and 800 Hz. To further study the behavior of such upward propagating ionospheric hiss wave during the seismic time, we compared the wave activities under non-seismic activity and quiet space weather conditions, and the results confirm that the occurrence rate of the upward propagating emissions under quiet conditions is far less than that in the seismic time. We suggest that there is a link between the upward propagating ionospheric hiss and the seismic activity, but the physical reason behind it still remains a puzzle to us.

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

The upward propagating ionospheric hiss waves during the seismic time observed by the China seismo-electromagnetic satellite

Lv¹,

Zhima³

et al. 2023

Front. Astron. Space Sci.

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Lightweight Automatic Detection Model for Lightning Whistle Waves Based on Improved YOLOv5

LU,

ZEREN,

YANG

et al. 2024

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The Typical ELF/VLF Electromagnetic Wave Activities in the Upper Ionosphere Recorded by the China Seismo-Electromagnetic Satellite

Hu,

Zhima,

Wang

et al. 2024

Remote Sensing

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Driven by the scientific objective of geophysical field detection and natural hazard monitoring from space, China launched an electromagnetic satellite, which is known as the China Seismo-Electromagnetic Satellite (CSES-01), on 2 February 2018, into a circular sun-synchronous orbit with an altitude of about 507 km in the ionosphere. The CSES-01 has been in orbit for over 6 years, successfully exceeding its designed 5-year lifespan, and will continually operate as long as possible. A second identical successor (CSES-02) will be launched in December 2024 in the same orbit space. The ionosphere is a highly dynamic and complicated system, and it is necessary to comprehensively understand the electromagnetic environment and the physical effects caused by various disturbance sources. The motivation of this report is to introduce the typical electromagnetic waves, mainly in the ELF/VLF band (i.e., ~100 Hz to 25 kHz), recorded by the CSES-01 in order to call the international community for deep research on EM wave activities and geophysical sphere coupling mechanisms. The wave spectral properties and the wave propagation parameters of those typical EM wave activities in the upper ionosphere are demonstrated in this study based on wave vector analysis using the singular value decomposition (SVD) method. The analysis shows that those typical and common natural EM waves in the upper ionosphere mainly include the ionospheric hiss and proton whistlers in the ELF band (below 1 kHz), the quasiperiodic (QP) emissions, magnetospheric line radiations (MLR), the falling-tone lightning whistlers, and V-shaped streaks in the ELF/VLF band (below 20 kHz). The typical artificial EM waves in the ELF/VLF band, such as power line harmonic radiation (PLHR) and radio waves in the VLF band, are also well recorded in the ionosphere.

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A Large‐Scale Magnetospheric Line Radiation Event in the Upper Ionosphere Recorded by the China‐Seismo‐Electromagnetic Satellite

Cited by 4 publications

References 43 publications

The upward propagating ionospheric hiss waves during the seismic time observed by the China seismo-electromagnetic satellite

The upward propagating ionospheric hiss waves during the seismic time observed by the China seismo-electromagnetic satellite

Lightweight Automatic Detection Model for Lightning Whistle Waves Based on Improved YOLOv5

The Typical ELF/VLF Electromagnetic Wave Activities in the Upper Ionosphere Recorded by the China Seismo-Electromagnetic Satellite

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