Understanding Jupiter's zonal winds is crucial to unraveling the dynamics of its atmosphere. Over the last decades, multiple data sources and techniques have been used to study zonal winds in Jupiter. Here, we develop a correlation-based method for the near-infrared data from the Cassini spacecraft to investigate zonal winds at different altitudes. The new method uses Jupiter's rotation to scan the planet as it rotates, allowing retrieval of winds from the analysis of light-curves of specific pixels over the Jovian disc. The method allows the retrieval of winds at multiple wavelengths from the Cassini/VIMS spectral data despite the low spatial resolution and the non-uniform cadence of the data. By applying this method to two VIMS data cubes acquired on 15 January 2001 at 09:42 UT and 16 January 2001 at 03:22 UT, we reveal the zonal winds at five main latitudes using information from three different wavebands, as well as the wind vertical structure at the equator, showing significant vertical wind shear in the troposphere. The vertical wind shear we derived is weaker than as reported in previous studies, highlighting the intricate interactions among multiple dynamical processes in Jupiter's atmosphere and reflecting the complexity of its atmospheric circulation. Despite the uncertainty due to the low spatial/temporal resolution and non-uniform cadence of the Cassini/VIMS-IR spectral data, the new method established in this study maximizes the value of the Cassini/VIMS in understanding Jupiter's zonal winds. Further observations are essential to explore the underlying mechanisms in Jupiter's atmosphere.

Heliophysics, a highly active and foundational frontier of contemporary natural science, stands as a critical interdisciplinary field encompassing solar physics, space physics, space weather and plasma physics. It is of paramount importance for understanding the physical processes of the Sun-Earth system and the solar system as a whole, as well as for ensuring the security of human high-technology activities in space. Since the successful launch of the first artificial satellite in 1957 ushered in a new era of space exploration, humanity has deployed hundreds of specialized spacecraft to investigate the myriad phenomena within our heliosphere. The synergistic use of remote sensing and in-situ measurements, integrated with extensive ground-based observations and sophisticated numerical models, has yielded numerous breakthrough discoveries. These advancements have profoundly enhanced our understanding of the Sun's influence on the solar system and the complex space environment surrounding Earth. This paper presents a comprehensive review of the current research status and future development trends in heliophysics, both domestically and within China. It synthesizes significant scientific achievements and cutting-edge advancements in recent years across four key domains: (1) the Sun and the heliosphere; (2) Earth's magnetosphere; (3) the ionosphere and the middle-upper atmosphere; and (4) the space environments of the Moon and other planets. Our analysis indicates that the international research paradigm is progressively expanding from a focused study of the "Sun-Earth system connection" to a holistic exploration of the "Sun-Solar System connection". Concurrently, technological advancements in wide-field imaging and constellation-based missions are significantly enhancing our observational capabilities for both macroscopic and meso-to micro-scale three-dimensional structures. Furthermore, comparative planetology and the study of planetary habitability are gaining increasing prominence. Domestically, China's heliophysics research has established a considerable ground-based monitoring network, is accelerating the construction of its space-based detection systems, and is continuously strengthening its academic foundations, leading to a steady emergence of original scientific outcomes. Looking toward the future, and aligned with the strategic deployment outlined in the recently released "National Space Science Mid-and Long-Term Development Plan (2024-2050)", this paper provides an in-depth discussion of ten critical scientific questions that China aims to address. These questions include: (1) the characteristics of magnetic activity in the solar polar regions and the formation mechanism of the solar magnetic cycle; (2) the cross-scale processes and mechanisms governing solar wind-magnetosphere interactions; (3) the processes and mechanisms of the solar wind's interaction with the interstellar medium; (4) the three-dimensional propagation characteristics of solar wind disturbances and the prediction of the southward magnetic field; (5) the influence of inner magnetospheric wave-particle interactions on the three-dimensional structure and evolution of radiation belts; (6) the coupling processes between the magnetosphere, ionosphere, and thermosphere, and the dynamics of polar particles; (7) the causes and variability of multi-scale disturbance structures in the ionosphere/thermosphere; (8) the coupling processes and mechanisms between Earth's geodynamic activity, atmosphere, and ionosphere; (9) the space weather environment and the mechanisms of matter and energy circulation in giant planet systems; and (10) the influence and mechanisms of space weather on planetary habitability. This paper aims to provide a comprehensive scientific reference for China's future deployment of research initiatives and strategic planning in heliophysics.

We present a database of 12 fast forward interplanetary (IP) shocks observed in situ by radially aligned spacecraft (Venus Express, Wind, and/or STEREO) between 2006 and 2014. By analyzing shock magnetic compression ratios at different heliocentric distances, which serve as a common proxy for shock strength, we found that five events displayed a decrease in shock strength from Venus (at similar to 0.72 au) to 1 au, five events showed no significant change within measurement uncertainties, and two events showed an increase near 1 au compared to Venus. Events that exhibited increased compression with distance may reflect specific interplanetary conditions that influence shock propagation and evolution. To investigate the causes of shock strengthening, we conducted a detailed case study of the 2011 March 18-21 shock event using a combination of multipoint remote-sensing and in situ observations. The analysis indicated that both the shock and its associated interplanetary coronal mass ejection (ICME) accelerated during their propagation, likely playing a major role in enhancing magnetic compression across the shock and contributing to the increased shock strength near 1 au. These findings highlight the importance of ICME kinematics in driving shock evolution in the inner heliosphere. The multi-spacecraft shock database compiled in this study also provides a valuable foundation for characterizing the radial evolution of IP shocks throughout the inner heliosphere.

Like Earth’s space, the Martian space constitutes a collisionless plasma environment. Consequently, the cross-scale energy transfer inherent to the multi-scale nature of collisionless plasmas—a process widespread in Earth’s space—is theoretically expected in Martian space. However, direct evidence for cross-scale energy transfer driven by cross-scale wave-particle interaction—the new model established in Earth’s space—remains elusive in Martian space. Utilizing data from the Mars Atmosphere and Volatile Evolution (MAVEN) and Tianwen-1 spacecrafts, we present the definitive observational evidence for the existence of such process in Martian foreshock region. Fast magnetosonic waves drive enhancements of electron perpendicular energy at their crests through Betatron acceleration, producing a perpendicular temperature anisotropy of the 20–200 eV population to supply the free energy for the excitations of whistler-mode waves. This process constitutes a direct manifestation of energy cascade from ion down to electron scales. Our study discovers a shared process in the terrestrial and Martian space, a finding that can carry broad implications for understanding space environments across planetary systems.

Interplanetary coronal mass ejections (ICMEs) are major drivers of heliospheric disturbances and space-weather effects. Here we present a multi-spacecraft study of 96 magnetic clouds (MCs) distributed over a broad range of heliocentric distances, and reconstruct their internal magnetic structure with a uniform-twist Gold–Hoyle (GH) flux-rope model. From the fits, we derive the axial field strength B_0, the twist density (turn density) τ, the GH parameter ω, and the integrated twist number n. We find that B_0 and the turn density τ both decrease with increasing heliocentric distance, consistent with expansion and axial stretching during propagation. A key result is that the upper envelope in the τ–R plane corresponds to a nearly constant boundary in the dimensionless GH parameter ω=2πRτ, close to ω∼2. Therefore, the inferred upper value of τ is not scale-independent, but follows τ_max≃ ω_max/(2πR) for a given flux-rope radius. In contrast, the estimated integrated turn number n shows no similarly clear radial organization in the present sample. This study investigates the ICME structure and magnetic field characteristics across heliocentric distances from 0.07 to 5.4 AU, thereby providing observational constraints on the large-scale evolution of interplanetary magnetic flux ropes.

Interplanetary coronal mass ejections (ICMEs) are major drivers of heliospheric disturbances and space-weather effects. Here, we present a multispacecraft study of 96 magnetic clouds (MCs) distributed over a broad range of heliocentric distances and reconstruct their internal magnetic structure with a uniform-twist Gold–Hoyle (GH) flux-rope model. From the fits, we derive the axial field strength B _0 , the twist density (turn density) τ , the GH parameter ω , and the integrated twist number n . We find that B _0 and the turn density τ both decrease with increasing heliocentric distance, consistent with expansion and axial stretching during propagation. A key result is that the upper envelope in the τ – R plane corresponds to a nearly constant boundary in the dimensionless GH parameter ω = 2 πRτ , close to ω ∼ 2. Therefore, the inferred upper value of τ is not scale independent but follows ${\tau }_{\max }\simeq {\omega }_{\max }/(2\pi R)$ for a given flux-rope radius. In contrast, the estimated integrated turn number n shows no similarly clear radial organization in the present sample. This study investigates the ICME structure and magnetic field characteristics across heliocentric distances from 0.07 to 5.4 au, thereby providing observational constraints on the large-scale evolution of interplanetary magnetic flux ropes.

As Solar Cycle 25 appears to approach the declining phase,to objectively evaluate the activity intensity during its rising phase and conduct a comparative analysis,we extend the catalog of Interplanetary Coronal Mass Ejections(ICMEs)from 2016 to 2025.Subsequently,we systematically compare and analyze the parameter characteristics and geoeffectiveness of ICMEs during the rising phase of Solar Cycle 25 with those of the previous two solar cycles.Overall,from 1995 to 2025,we identify 657 ICME events,which are classified into 530 groups and are associated with a total of 325 geomagnetic storms,including 103 intense geomagnetic storms.The annual occurrence frequencies of ICMEs,the number of ICME groups and their associated geomagnetic storms are largely synchronized with the variations in sunspot numbers.The sunspot numbers during the rising phase of Solar Cycle 25 are comparable to those of Solar Cycle 23 and clearly higher than those of Solar Cycle 24.Compared with the previous two solar cycles,Solar Cycle 25 exhibits the smallest number of ICMEs during its rising phase.The numbers of geomagnetic storms and intense geomagnetic storms during this period fall between those of the two preceding cycles,consistent with the overall variation in solar activity.Although the number of intense geomagnetic storms during the rising phase of Solar Cycle 25 is relatively small,their intensities are remarkably high,with several extremely intense storm events observed.During the rising phase of Solar Cycle 25,the average values of the magnetic field strength,southward magnetic field component,and dawn-dusk electric field of ICMEs are the highest among the three periods.They are key parameters influencing the geoeffectiveness of ICMEs.Overall,the geoeffectiveness of ICMEs during the rising phase of Solar Cycle 25 is intermediate between those of the previous two cycles.

Abstract Plasmaspheric plume hiss plays a crucial role in shaping Earth's electron radiation belts and influencing magnetosphere–ionosphere energy coupling. However, its generation mechanism remains contested between cyclic‐linear and localized‐nonlinear models. By analyzing over 64,000 high‐resolution plume hiss wave segments from the Van Allen Probes (1 January 2013–31 July 2019), we identify a distinct frequency dependence in their latitudinal distributions of directionality and amplitude. For high‐frequency hiss, bidirectional propagation is sharply confined near the magnetic equator, beyond which poleward‐propagating waves overwhelmingly dominate, and the wave amplitude increases obviously with latitude. These signatures are consistent with a rapid, single‐pass, equatorially confined, nonlinear amplification process. In contrast, low‐frequency hiss exhibits a high prevalence and wide latitudinal extension of bidirectional propagation, with relatively smooth amplitude variations. This pattern supports a generation scenario involving slower growth, potentially linear or nonlinear, that is coupled with wave bounce motion along magnetic field lines.

Photospheric horizontal velocity fields play essential roles in the formation and evolution of numerous solar activities. Various methods for estimating the horizontal velocity field have been proposed in the past. Aiming at the highest available (and future) spatial resolution (10 km pixel ^−1 ) observations, a new method, the Shallow U-net models (SUVEL), based on realistic numerical simulation and machine learning techniques, was recently developed to track the photospheric horizontal velocity fields. Although SUVEL has been tested on numerical simulation data, its performance on solar observational data remained unclear. In this work, we apply SUVEL to the photospheric intensity observations from four ground-based solar telescopes (DKIST, GST, NVST, and SST) with the largest available apertures, and compare the results obtained from SUVEL with the Fourier local correlation tracking method (FLCT). Average correlation indices between granular regions and velocity fields inferred by SUVEL (FLCT) are 0.63, 0.81, 0.80, and 0.87 (0.00, 0.11, 0.16, and 0.10) for DKIST, GST, NVST, and SST observations. Higher correlation indices between the velocity fields tracked by SUVEL and granular patterns than FLCT reveal the superior performance of SUVEL, validating its reliability with respect to solar observational data.

Context. Detecting faint and cross-shaped sources in long-exposure images from lobster-eye X-ray telescopes is particularly challenging due to the low signal-to-noise ratio (S/N), complex noise, and unique point spread function (PSF) of these instruments. Conventional deep learning networks struggle in such conditions as they fail to effectively incorporate astrophysical priors such as photon arrival time, energy, and PSF morphology. Furthermore, the significant flux-scale differences between faint and bright sources complicate feature extraction in the standard feature pyramid network (FPN). Aims. The goal is to propose a PSF-guided multi-scale detection framework that integrates prior physical features and is specifically designed for the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP). Methods. Our approach began by constructing three-channel inputs, combining conventional grayscale images with photon energy and arrival time data. We then introduced a PSF-guided morphological convolution module (PSFConv) and a multi-kernel multi-scale FPN (MKMS-FPN) to enhance the extraction of morphological features and improve multi-scale target perception. Additionally, we integrated high-level convolutional features with prior physical statistics within a multibranch binary classifier of our detection network to boost both detection sensitivity and interpretability. Results. Using simulated long-exposure WXT data and in-orbit EP observations, our framework achieves 90% precision with recall rates of 0.85 and 0.95 for sources with flux >2 mCrab (i.e. 3.21 × 10−11 erg cm−2 s−1, unabsorbed, 0.5-4 keV) and flux >3 mCrab, respectively. At moderate precision levels, the framework further doubles the number of detectable sources with flux < 1 mCrab compared to conventional CNNs and the SExtractor pipeline. Conclusions. The integration of physical priors with deep convolutional features demonstrates a robust detection performance across diverse flux regimes. The proposed framework offers a practical reference for data processing in future lobster-eye X-ray missions, promising enhanced sensitivity for detecting faint sources in challenging astrophysical observations.

Using the Correlation-Aided Reconstruction (CORAR) technique, we identified a population of small transient structures in the near-Sun solar wind observed by the white-light coronagraphs on board STEREO between 2009 December and 2010 September. After excluding partial structures of large-scale coronal mass ejections (CMEs), we manually classified the remaining events into two distinct types: CME-related and CME-unrelated events, and systematically analyzed differences in their propagation characteristics. We find that CME-related events exhibit relatively higher propagation velocities than CME-unrelated events at the same heliocentric distance, and tend to maintain acceleration at greater distances. Additionally, the propagation speeds of CME-unrelated events within different ranges of theta HCS (the angular distance from the heliospheric current sheet, HCS) exhibit comparable magnitudes, suggesting that the empirical relationship between theta HCS and heliospheric solar wind speed is not applicable to the near-HCS transient outflows in the extended corona. We discuss the factors contributing to different propagation behaviors of these small events, as well as their underlying mechanisms, and provide a valuable comparison between the observations and the solar wind simulation by the Magnetohydrodynamic Algorithm outside a Sphere (MAS) coronal model. This work advances our understanding of the origin and evolution of different solar wind transients. It provides unique insights into the transition of released outflows from the Sun to interplanetary solar wind, which is significant for the improvement of solar wind models and coronal simulations.

Why is Earth, among the eight planets in our solar system, the only habitable one? Over the 4.6-billion-year evolution of the solar system, why did Mars and Venus evolve so differently? Where did life originate, and how will Earth evolve in the future? These questions are not only central to planetary science in the 21st century but are also deeply connected to humanity’s fundamental understanding of its own existence and planetary habitability. Addressing these grand scientific challenges demands a systematic, multidimensional research approach. In the temporal dimension, we need to trace the early formation and evolution of terrestrial planets; in the spatial dimension, we need to analyze the layered structure of planets and the coupling between these layers; from a comparative perspective, we also need to explore the atmospheric characteristics of exoplanets and the influence of their host stars on habitability. Supported by the Chinese Academy of Sciences’ Strategic Priority Research Program on “Formation, Evolution, and Habitability of Terrestrial Planets,” we have taken planetary habitability as the main research theme and conducted systematic, in-depth studies on terrestrial planets by integrating multiple approaches, including extraterrestrial sample analysis, deep-space exploration data processing, and numerical and experimental simulation. This paper comprehensively summarizes the significant advancements made by the project over the past five years. It covers topics ranging from the early processes and environmental evolution of terrestrial planets to open planetary systems linked to the external space environment, and from Earth’s Moon to exoplanets. Key achievements include the first confirmation of a solid inner core on Mars, revealing its core-mantle differentiation under high-pressure and high-temperature conditions, and the discovery that the youngest lunar basalts originated from a non-KREEP, volatile-poor mantle source region, challenging the long-held traditional hypothesis that “volatile-rich material drives late-stage volcanism”—a textbook-level achievement. While summarizing the latest research advances, this paper also looks toward future directions. Significantly improving the capability for multi-layered, multi-parameter detection of planets, especially global planetary survey capabilities, and vigorously developing related techniques and research methods, particularly the application of cutting-edge technologies such as quantum technology and artificial intelligence, will be the key to achieving further major breakthroughs in planetary science. By sharing these research findings and insights, we aim to inspire more young people to pursue careers in planetary science—a field full of opportunities and challenges—thereby promoting the sustainable development of planetary science in China and over the world.

Juno in situ observations provide insightful data on plasma, electric, and magnetic fields associated with Jovian decametric (DAM) emission, while remote-sensing observations offer broader spatial and temporal coverage. Combining both perspectives may help us understand the dynamic processes of DAM radiation. In this work, we present an Io-related DAM emission continued intermittently for at least 2 hr, observed by Juno in situ and remotely by Wind and STEREO-A. The Io-DAM emission evolved from three discrete narrow arcs to one mixed broad arc within 11 minutes in remote-sensing dynamic spectra. The source remained near a lead angle of 6° from the main Alfvén wing spot during the observation. Juno/JADE detected peaks in electron energy flux and an upward loss-cone distribution. Using a set of resonance circles, we estimate a maximum growth rate γ / ω _c of 6.4 × 10 ^−4 , corresponding to electron energies of 0.2–10 keV and emission angles of 77°–88°. Meanwhile, we infer the properties of the source region of the event from the remote-sensing observations at 1 au. The inferred results on electron energy, emission angle, and source locations are consistent with the Juno in situ observations, suggesting the consistent properties of this Io-DAM event over 2 hr observational intervals. This consistency also reinforces the reliability of the remote sensing inversion method. Our work contributes to the establishment of long-term stereoscopic remote monitoring, addressing limitations in local observational coverage and enhancing our understanding of the dynamic processes of DAM emission.

Jets, as an essential manifestation of the release of the free magnetic energy, are ubiquitous in the solar atmosphere. We present a comprehensive analysis of a multithermal blowout jet that occurred in active region AR 13102 on 2022 September 20, using observations from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly, SDO/Helioseismic and Magnetic Imager (HMI), Interface Region Imaging Spectrograph, and Solar Upper Transition Region Imager. The jet is initiated by compact brightenings at its footpoints and exhibits a curtain-like spire with apparent rotational and weak lateral whipping motions. Time-distance analysis reveals a projected axial velocity similar to 300 km s-1 and a rotational speed similar to 30 km s-1. Differential emission measure analysis shows that the jet plasma spans a broad temperature range, with hot (greater than or similar to 10 MK) plasma concentrated near the flare loops and jet base and cooler components extending along the spire. Using the derived kinetic and thermal properties, we conclude that there is an equipartition between the jet's kinetic energy (5.4 +/- 2.4) & times; 1020 J and thermal energy (7.0 +/- 3.6) & times; 1020 J. HMI vector magnetograms and nonlinear force-free field extrapolations reveal that the jet originates from a compact mixed-polarity region at the edge of the active region, where flux emergence and cancellation, a low-lying twisted magnetic flux rope with a maximum twist number of similar to 2.1, and a surrounding high-Q quasi-separatrix layer are present. The observed decrease in twist after the eruption, together with the jet's untwisting, indicates that the jet is driven by the eruption and the reconnection of the twisted flux rope, converting magnetic free energy into plasma heating and bulk motion. Our results highlight the importance of small-scale flux rope eruptions in driving blowout jets and releasing twist through magnetic reconnection and untwisting motions.

Coronal mass ejections (CMEs), since their first observation in 1971, have been widely acknowledged as the most significant eruptive phenomena and the primary cause of catastrophic space weather events within our solar system. Whether similar processes involving stellar mass ejections (SMEs) occur on other stars holds immense potential for advancing our understanding of stellar behavior and providing insights into the search for extraterrestrial life. However, detecting SMEs remains challenging, particularly in establishing reliable approaches and diagnostics. Here, we conduct a proof-of-concept Sun-as-a-star experiment using solar CMEs as proxies, analyzing EUV spectral lines from the Extreme Ultraviolet Variability Experiment on board the Solar Dynamics Observatory. By comparing 26 front-side fast CMEs with 14 confined flares of class M 1.0 and above, we find that the Doppler responses in 18.04, 19.51, and 28.42 nm during CME events provide a promising diagnostic to distinguish Sun-as-a-star CME signals from flare features. We further show that CME characteristics can be reasonably reproduced from the Doppler velocities in these three lines, providing a hopeful diagnostic for inferring otherwise unobservable properties of eruptions on remote stars. These findings advance the exploration and understanding of mass ejections in stars. We therefore advocate the resumption of the EUV observations of extrasolar stars.

The interaction between planetary atmosphere and stellar winds governs atmospheric evolution in unmagnetized planets. Generally, an interplanetary magnetic field (IMF) drapes around the planetary ionosphere, creating a magnetic barrier that deflects stellar winds and leads to the formation of an induced magnetosphere. However, whether an induced magnetosphere can form under radial IMF conditions where the IMF aligns with solar wind flow in our Solar System remains controversial. By analyzing joint observations from the Tianwen-1 orbiter and the Mars Atmosphere and Volatile Evolution mission combined with hybrid numerical simulations, we clearly demonstrate the formation of Mars’ induced magnetosphere during the radial IMF for the first time. This induced magnetosphere comprises a draped magnetic field and an induced magnetic field. Magnetic pressure buildup above the ionosphere surpasses incident solar wind pressure, which establishes a stable magnetic barrier. This finding indicates that the draped magnetic field still forms under a radial IMF. The formation of Mars’ induced magnetosphere under the radial IMF could be a general pattern for the interaction between the IMF and planetary atmosphere, which can be referred to terrestrial exoplanets within the close-in habitable zone of dwarf stars. This work clarifies the fundamental understanding of solar wind interactions with unmagnetized planets across diverse solar wind conditions.

Coronal holes (CHs) are the darkest regions observed on the Sun, serving as key sources of open magnetic fields and fast solar-wind streams. Accurate and consistent delineation of their boundaries is crucial for analyzing their physical properties, understanding solar dynamics, and ultimately improving space weather forecasts. However, developing precise and automated methods for their detection and tracking across extensive observational datasets remains a significant challenge. To address this, we developed the DEtection and Tracking Algorithm for Coronal Holes (DETACH), leveraging advanced machine-learning techniques. DETACH was specifically developed and rigorously validated using extreme ultraviolet (EUV) 193 Å wavelength images from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) instrument. This novel algorithm significantly advances prior CH detection models, notably minimizing the erroneous identification of solar filaments as CHs and achieving superior accuracy across a comprehensive suite of evaluation metrics. Additionally, another key innovation of DETACH is its robust and precise CH tracking functionality across different observational times, a crucial capability largely absent in previous methodologies. DETACH offers a state-of-the-art, high-performance solution for accurate coronal hole identification and tracking, providing invaluable data and a powerful tool to enhance our understanding of solar activity and advance space-weather prediction capabilities.

In May 2024, NOAA active region (AR) complex 13664/8 was one of the most productive regions of the current solar cycle, producing 12 X-class flares and over 20 coronal mass ejections (CMEs) and triggering the strongest geomagnetic storm since 2003. We investigate why this AR complex was so CME-productive. Using primarily SDO/AIA and SDO/HMI observations, we analyzed its photospheric magnetic evolution, eruption sources, eruption waiting times, and magnetic parameters in comparison with five other ARs. The region initially contained only AR 13664 and exhibited limited flare activity until AR 13668 emerged on May 4, after which clustered major flares and CMEs occurred. Rapid, complex flux emergence substantially increased the region's area, magnetic flux, complexity, and nonpotentiality. The increased complexity was manifested by at least 12 emerging bipoles and six collisional polarity inversion lines (cPILs) formed between nonconjugated polarities, all showing sustained collision and shearing and serving as eruption sources. Decay index distributions show systematically lower critical heights (<45 Mm) above CME source regions. The CME waiting time distribution exhibits two peaks, suggesting that multiple cPILs enhanced CME productivity by increasing both recurrent CMEs from the same source and disturbance-triggered CMEs from nearby sources. These results indicate that, in addition to sufficient nonpotentiality and rapid background-field decay, high magnetic complexity accompanied by dynamical collisional shearing at multiple cPILs was crucial for the extreme CME productivity of AR 13664/8.

Abstract Interactions between the ionospheres of unmagnetized bodies and ambient plasma flows form induced magnetospheres. The induced magnetosphere is generally affected by external magnetic fields. Observations of response processes of the induced magnetosphere to external magnetic fields are important for understanding global dynamical processes in unmagnetized planets. Here, using simultaneous observations of Tianwen-1 and Mars Atmosphere and Volatile EvolutioN missions, we show the response of Mars’ induced magnetosphere to interplanetary magnetic field (IMF) rotation. The magnetic field in Mars’ induced magnetosphere rotated within at least 165 seconds following the sudden IMF clock-angle change and gradually stabilized. The convective electric field rotated accordingly, bringing the pickup oxygen-ion plume into the spacecraft’s field of view within 3 minutes. These short timescales demonstrate that Mars’ induced magnetosphere is highly dynamic and sensitive to external magnetic-field variations. IMF changes should therefore be regarded as a common form of Mars’ space weather, highlighting the importance of upstream IMF monitoring and short-term forecasting.