## 1 Introduction  
Within the solar-terrestrial system, the ionospheric layers can mirror both Earthward and Sunward disturbances at various scales. From the Earth direction, namely from the lithosphere or atmosphere, the disturbances include the relatively weak but detectable seismic precursor anomalies [1], the strong radio waves emitted by powerful ground-based very low frequency (VLF) transmitters [2], the harmonic radiation from the electric power lines [3], and the strong whistler-mode waves induced by lightning/thunderstorms in the atmosphere. From the Sun direction, the disturbances coming from above the ionosphere are mainly related to the Sun, which releases coronal mass ejections (CMEs) and solar flares, as well as the resultant geomagnetic storm/substorm activity. In particular, there is a magnetic field-line mapping of the magnetosphere onto the high-latitude ionosphere, along which field-line currents, possibly associated with magnetospheric polarization fronts, enter the post-midnight ionosphere and leave it from the pre-midnight side, thus feeding the strong aurora electrojet [4; 5]. This makes the ionosphere a highly dynamic system where a variety of intense electromagnetic emissions and energetic particle precipitations are detected due to multiple layer interactions with the lithosphere, atmosphere, and magnetosphere, as well as solar wind [4; 5; 6; 7; 8]. The electromagnetic emissions excited in the extremely/very low frequency (ELF/VLF) range [9; 10; 11; 12; 13] are the most direct outcomes of this dynamic system. The most commonly observed typical electromagnetic waves at ELF/VLF bands are the whistler-mode waves [9; 14; 15; 16; 17; 18], which include the whistler-mode VLF chorus [12; 16; 19], quasi-periodic waves [13; 15; 20], ELF hiss [21; 22; 23], and strong whistlers induced by lightning, VLF radio wave transmitters, or other sources [22; 24]. These typical whistler-mode waves play significant roles either in the acceleration or loss process of relativistic electrons in the Earth's outer radiation belt [14; 17; 25]. The VLF chorus mainly appears at frequency from 0.1 to 0.8 \(f_{\rm ce}\) (the equatorial electron cyclotron frequency) and can efficiently accelerate relativistic electrons (\(E>\) MeV) [14]. [PERSON] et al. [10] firstly found the evidence of whistler-mode chorus penetrating the plasmapause and entering into the low altitude ionosphere, and [PERSON] et al. [26] firstly reported that chorus waves in the magnetosphere accelerated energetic electrons (1-3 MeV) in the ionosphere from the China Seismo-Electromagnetic Satellite (CSES) observations. ELF hiss waves are structure-less and incoherent electromagnetic waves that preferentially appear at a broad frequency range from several hundred Hz to 3 kHz, playing vital roles in either the loss of energetic electrons or the formation of radiation belt slot region [22; 27; 28]. Another important ELF/VLF whistler-mode wave often appearing in the ionosphere is the quasi-periodic (QP) wave at frequencies from several hundred Hz to \(\sim\)4 kHz with varying periodic modulations of wave intensity over time scales from several seconds to a few minutes; they are often observed by low Earth orbit (LEO) satellites and ground stations [13; 15]. [PERSON] et al. [20] reported the well-pronounced rising-tone structure QP waves and simultaneous energetic electron precipitations (from \(\sim\)400 keV to 1 MeV) in the high-latitude ionosphere firstly based on the CSES's observations. Because they are simultaneously observed with the strong ELF/VLF wave activity, changes in the fluxes of energetic particle populations are usually checked for. In the context of radiation-belt dynamics, it is widely accepted that ELF/VLF whistler-mode waves represent the main candidate for the acceleration/loss of particles during storm time [17; 29], so they have been given increasing attention due to their impact on the dynamics of near-Earth space. [PERSON] et al.