First Results of the Wave Measurements by the WHU VLF Wave Detection System at the Chinese Great Wall Station in Antarctica

Abstract

The Extremely Low Frequency (ELF) and VLF waves, with frequencies typically ranging from 300 Hz to 30 kHz, can be categorized as the naturally occurring waves and artificial emissions (e.g., Cohen et al., 2010;Ni et al., 2022). Lightning discharges and man-made VLF transmitters are the two dominant sources of ELF/ VLF waves that repetitively reflect and propagate within the Earth-ionosphere Waveguide (EIWG) (e.g., Barr et al., 2000;Silber & Price, 2016). With wavelengths of 10-1000 km, these waves are well bounded by the terrestrial surface and the lower ionosphere, and can thus propagate thousands of kilometers with relatively low attenuation (∼2 dB/Mm) (e.g., Davies, 1990;Sasmal, 2018). As such, the propagation of ELF/VLF waves is primarily influenced by the variation of the lower and upper boundaries of EIWG, especially a region that Abstract A Very Low Frequency (VLF) wave detection system has been designed at Wuhan University (WHU) and recently deployed by the Polar Research Institute of China at the Chinese Great Wall station (GWS, 62.22°S, 58.96°W) in Antarctica. With a dynamic range of ∼110 dB and timing accuracy of ∼100 ns, this detection system can provide observational data with a resolution that can facilitate space physics and space weather studies. This paper presents the first results of the wave measurements by the WHU VLF wave detection system at GWS to verify the performance of the system. With the routine operation for 3 months, the system can acquire the dynamic changes of the wave amplitudes and phases of various ground-based VLF transmitter signals emitted in both North America and Europe. A preliminary analysis indicates that the properties of the VLF transmitter signals observed at GWS during the X-class solar flare events are consistent with previous studies. As the HWU-GWS path crosses the South Atlantic Anomaly region, the observations also imply a good connection in space and time between the VLF wave disturbances and the lower ionosphere variation potentially caused by magnetospheric electron precipitation during the geomagnetic storm period. It is therefore well expected that the acquisition of VLF wave data at GWS, in combination with datasets from other instruments, can be beneficial for space weather studies related to the radiation belt dynamics, terrestrial lightning discharge, whistler wave propagation, and the lower ionosphere disturbance, etc., in the polar region. Plain Language Summary Considering the good coverage and quiet electromagnetic environment,Antarctica is an ideal place for plasma wave measurements. Various stations have been established in Antarctica, of which Palmer station is particularly noteworthy and has historically provided valuable VLF data for atmospheric, ionospheric, and magnetospheric studies. An Extremely Low Frequency/Very Low Frequency (VLF) wave detection system has been designed by Wuhan University and recently set up at Great Wall station (GWS) in Antarctica. This device can effectively record VLF signals with frequencies of 1-50 kHz, including...

Periodic Oscillation of VLF Transmitter Signals Measured in Low and Middle Latitude Regions

“…This receiver is highly sensitive, with a dynamic range of ∼110 dB and a timing accuracy of ∼100 ns (Gu et al., 2023; Xu, Gu, et al., 2023). Two triangle‐shaped magnetic loop antennas were set up at the Suizhou station, one oriented along the East‐West direction and the other one along the North‐South direction (Gu, Wang, et al., 2022), constituting an orthogonal two‐channel system. The instrument is maintained regularly and this receiver has been operating reliably for the years of 2016 and 2022.…”

“…The VLF data utilized in this study were collected in Suizhou, China (31.57°N, 113.32°E) and by a receiver developed by Wuhan University: the WHU ELF/VLF wave detection system (Chen et al., 2016; Gu, Peng, et al., 2022). This receiver can detect VLF signals in the frequency range of 1–50 kHz (Gu, Wang, et al., 2022). This receiver is highly sensitive, with a dynamic range of ∼110 dB and a timing accuracy of ∼100 ns (Gu et al., 2023; Xu, Gu, et al., 2023).…”

Measurements and Modeling of the Responses of VLF Transmitter Signals to X‐Class Solar Flares at the Great Wall Station in Antarctica

“…The VLF receiver utilized in the present study was recently installed at the GWS station in Antarctica (Gu et al., 2022). GWS is ∼370 km away from the Palmer station in Antarctica, the VLF receiver at which was maintained by the Stanford VLF group (M. Cohen, 2020; M. B. Cohen et al., 2009) and has been highly successful in subionospheric studies (Inan et al., 2010).…”

Automatic Detection of VLF Tweek Signals Based on the YOLO Model

“…In this paper, we use the data collected using the VLF detection system developed by Wuhan University [39][40][41]. The receiver consists of two orthogonal magnetic loop antennas, set up in both East-West (EW) and North-South (NS) directions.…”