空间科学学报

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Evolution Prediction Model of Equatorial Plasma Bubbles Based on SimVP

ZHONG Jia, ZOU ZiMing, WU Kun, XU JiYao, LU Yang, SUN Longcang, YUAN Wei

, Available online , doi: 10.11728/cjss2026.02.2025-0046

Abstract(381) FullText HTML (49) PDF 5175KB(33)

Abstract:
Equatorial Plasma Bubbles (EPBs) are large-scale depletion structures characterized by significantly reduced electron density, which frequently emerge in the low-latitude ionosphere during post-sunset hours. These dynamic plasma irregularities play a crucial role in space weather phenomena, as their evolution can induce severe amplitude and phase scintillations in radio signals, leading to disruptions in satellite communications, global navigation systems, and radar operations. Given their substantial impact on technological systems, accurate prediction of EPB evolution has become a critical challenge in both space physics research and operational space weather forecasting.. To address this challenge, this study introduces a novel data-driven approach for EPB evolution prediction by leveraging the SimVP (Simpler yet Better Video Prediction) framework, an advanced deep learning architecture designed for spatiotemporal sequence forecasting. The proposed model learns the complex nonlinear dynamics of EPB structures from historical airglow image sequences, capturing both their morphological transformations and drift patterns. Through extensive experimentation, we systematically evaluate the influence of key parameters—including time resolution, input/output sequence length, and environmental noise—on prediction performance. Our findings demonstrate that an optimal configuration with a 3 min temporal resolution and a 6-frame input/output structure achieves superior predictive accuracy, as evidenced by high Structural Similarity (SSIM=0.989) and Peak Signal-to-Noise Ratio (PSNR=34.704) metrics. Further analysis reveals that the spatial complexity of EPB structures, such as bifurcation events and irregular boundary deformations, significantly affects prediction fidelity, whereas the impact of light pollution—a common issue in ground-based airglow observations—is comparatively minor. The model proposed in this paper demonstrates robust cross-station applicability. Beyond forecasting, the model also exhibits potential for reconstructing corrupted airglow data, offering a computational solution to enhance observational datasets affected by atmospheric or instrumental noise. This work not only establishes a robust, machine learning-based tool for EPB evolution analysis but also contributes to the broader development of Artificial Intelligence (AI) applications in space weather modeling and ionospheric research.

A Dataset of Geomagnetic Kp_est Index from Individual Stations (2022－2024)

WANG Jing, ZHONG Qiuzhen, LUO Bingxian, WANG Xiao, ZHAO Mingliang, CHENG Yonghong, SHEN Hua

, Available online , doi: 10.11728/cjss2026.02.2025-0131

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Abstract:
The Kp index is a parameter designed to indicate the level of global geomagnetic disturbances originating from the interaction of the solar wind with the magnetosphere. The index is defined at 3-hour intervals and has 28 levels. Kp is a global version of the local K index, which was conceived by Bartels and is commonly used in scientific research of the solar-terrestrial relationship. The continuity of the index over 50 year makes it particularly valuable in studies of solar-cycle variations and other long-term effects on interplanetary and magnetospheric phenomena. For example, Kp has been used in studies of solar wind shock waves, the interplanetary magnetic field, plasma density variations in the magnetosphere, and magnetospheric ULF waves. In addition, the index is widely used as an input to magnetospheric/ionospheric models. For example, the plasmapause is modeled to move closer to the Earth with increasing Kp. The location of substorm injection is modeled to have a similar Kp dependence. The magnetic field model of Tsyganenko has an explicit Kp dependence, and the magnetotail becomes more stretched for higher Kp. These models are used both in scientific research and in monitoring and predicting space weather. In 2011, the National Space Science Center of the Chinese Academy of Sciences established the Chinese Academy of Sciences Space Environment Monitoring Network, which included Mohe, Beijing, Langfang, Sanya, and Fuke stations. A geomagnetic Kp_est index, which can effectively identify the day-to-day variation characteristics of the geomagnetic regular daily variation, reflect the seasonal and local time effects of geomagnetic disturbances, and is suitable for the distribution characteristics of China’s geomagnetic observatory network, has been developed through the integration and processing of the H-component monitoring data from fluxgate magnetometers at these five geomagnetic observatory stations. This dataset contains the geomagnetic Kp_est indices for the five geomagnetic observatory stations from 2022 to 2024. It addresses the current situation where the official Kp index is released with a two-week delay, failing to meet operational requirements, and can provide data support for space weather forecasting services.

Cosmic Ray Muon Count Dataset from Siziwang Station in Inner Mongolia (2023－2025)

CHENG Yonghong, ZHONG Qiuzhen, ZHUANG Chunbo, SHI Liqin, SONG Xiaochao, WANG Jing, SHEN Hua, WEI Lihang

, Available online , doi: 10.11728/cjss2026.02.2025-0133

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Abstract:
The Muon Telescope at Siziwang Station in Inner Mongolia is used to detect the secondary cosmic ray muons reaching the ground. The Muon Telescope began construction in November 2019, was completed in April 2023, and produced scientific data. The muon telescope consists of a scintillator observation stack, an electronics recorder, a monitoring platform, and a power supply. The scintillator observation stack is composed of 48 detector units, divided into upper and lower layers with 24 units in each layer, arranged in a 6×4 array. In each detector unit, the plastic scintillator has dimensions of 50 cm × 50 cm × 5 cm. The distance between the upper and lower layers is 89 cm. A 5cm-thick layer of lead bricks is laid between the upper and lower layers to filter out low-energy cosmic rays and low-energy particles in the surrounding environment. The detectors have a total area of 6 m². Muon signals generated by the 48 detector units of the Muon Telescope are processed through front-end circuits for amplification, discrimination, and shaping, then sent to the FPGA logic circuit for directional coincidence calculation. This produces raw muon counts in 15 directions. After undergoing barometric correction calculation, a dataset of corrected muon counts in 15 directions is formed, with a temporal resolution of 1 hour. The count rate in the vertical direction is the highest, with the 1-hour count rate being around 600,000 counts and the relative statistical error approximately 0.13%. The muon data can sensitively reflect diurnal variations, long-term variations of cosmic rays, and short-term Forbush decrease perturbations induced by coronal mass ejections. Spanning from May 2023 to April 2025, this dataset covers the high-activity phase of the 25th solar activity cycle. It provides valuable data resources for research on solar eruptions, their interplanetary disturbance propagation, and geomagnetic response processes, while also supporting space weather early warning efforts.

Design and Implementation of a High-performance Image Compression Core for Spaceborne Applications

FU Zhiyu, ZHANG Xuequan

, Available online , doi: 10.11728/cjss2026.01.2025-0021

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Abstract:
To address the critical need for efficient image storage and transmission in aerospace applications, this study presents a CCSDS 122.0-B-1-compliant compression core implemented on FPGA. The design incorporates innovative encoding control logic and optimized data organization through co-optimization of algorithmic features and hardware constraints. A segment-based architecture with 256-pixel blocks achieves superior compression efficiency among existing solutions, while effectively containing error propagation through segmented compression. The architecture further enables continuous quality adaptation and progressive image transmission. To resolve performance bottlenecks in scanning and encoding processes, fully parallelized scanning with adaptive parallel encoding was developed, and a 50% efficiency improvement was demonstrated in validation tests. Supporting images up to 4096×4096 pixel with 16-bit depth, the core delivers 90.64×10⁶sample·s^–1 throughput, meeting operational requirements for diverse space missions.

Design of Finite Frequency Domain Disturbance Rejection Controller for the Drag-free Spacecraft in Space-borne Gravitational Wave Detection

XU Qianjiao, CUI Bing, WANG Pengcheng, XIA Yuanqing, ZHANG Yonghe

, Available online , doi: 10.11728/cjss2024.05.2024-0022

Abstract(1060) FullText HTML (388) PDF 5881KB(76)

Abstract:
In space-borne gravitational wave detection, there are technical challenges in designing the controller for the drag-free spacecraft with dual test masses. These difficulties arise from constraints within the limited measurement frequency domain and the necessity for a high-precision control index. In this paper, a design method of disturbance rejection controller in the finite frequency domain based on the generalized Kalman-Yakubovich-Popov (GKYP) lemma is proposed. Firstly, to address the performance constraints within the designated frequency band of the detection mission, a finite frequency domain control performance index in the form of a frequency response function is constructed. This index is meticulously developed by amalgamating the sensitivity and complementary sensitivity control indexes. Then, a control structure with fixed-order characteristics for output feedback is proposed, and a method for selecting controller parameters based on the GKYP lemma is established. By this, a finite frequency domain disturbance-resistant controller design method is constructed. In contrast to current drag-free controller design methods, the proposed approach significantly diminishes the conservatism in the control index. This realizes the precise design of the controller in the specified frequency band, ultimately resulting in a reduction in the order of the controller. Finally, numerical simulations demonstrate that the proposed method successfully meets the control performance index for each loop of the drag-free system even in the presence of complex disturbances and noises.