Journal of Geophysical Research: Space Physics最新文献

{"title":"Intensity Pattern of Auroras Based on Eighteen-Year Observations From DMSP Satellites","authors":"Qinpei Yin,&nbsp;Sai Zhang,&nbsp;Desheng Han,&nbsp;Yuyue Jin,&nbsp;Fuliang Xiao,&nbsp;Si Liu,&nbsp;Jiawen Tang,&nbsp;Sanguang Li,&nbsp;Liang Hu","doi":"10.1029/2026JA035437","DOIUrl":"https://doi.org/10.1029/2026JA035437","url":null,"abstract":"<p>Auroras are luminous atmospheric phenomena generated by collisions between energetic charged particles and neutral atmospheric species. Despite their scientific importance, studies on the spatiotemporal variations in auroral intensity remain limited due to a lack of long-term, continuous observations. In this study, we analyze the distribution characteristics of auroral intensity using 18 years of observations (1 January 2005–31 December 2022) from three Defense Meteorological Satellite Program (DMSP) satellites. Our results reveal a significant positive correlation (coefficient ≈ 0.65) between the annual mean auroral intensity and sunspot number, confirming a close link between auroral intensity and solar activity. Notably, a pronounced north-south hemispheric asymmetry is observed in auroral peak intensity, with the northern hemisphere reaching 741 Rayleigh and the southern hemisphere only 465 Rayleigh. Seasonally, auroral intensity peaks in spring (northern hemisphere) and autumn (southern hemisphere), with the minimum intensity observed in winter for both hemispheres. This seasonal variation in auroral intensity is likely associated with the global distribution of field-aligned currents. This study further enriches the information and understanding of the spatial and periodic properties of auroral activity, and thus contributes to a deeper insight into magnetosphere-ionosphere-atmosphere coupling.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classifications of Substorms With MLT Patterns of SMU-SML Indices Based on Convection Properties","authors":"Shan Wang,&nbsp;Lei Dai,&nbsp;Colin Forsyth,&nbsp;Chao Yue,&nbsp;Chao Xiong,&nbsp;Hao-Bo Fu,&nbsp;Qiu-Gang Zong,&nbsp;Yan Zhuang,&nbsp;Boyi Wang,&nbsp;Christian Lao,&nbsp;Yi-Xin Sun,&nbsp;Si-Bo Xu","doi":"10.1029/2026JA035629","DOIUrl":"https://doi.org/10.1029/2026JA035629","url":null,"abstract":"<p>During substorms, magnetospheric convection and magnetotail current sheet disturbances are two critical processes, both driving ionospheric electrojets. Dusk-side SMU and dawn-side SML (SuperMAG Electrojet indices) enhancements reflect two-cell convection. Using this relation, we categorize substorms with different convection properties near onset. When primary SML enhancements occur near midnight, the presence or absence of dusk-side SMU/dawn-side SML activity distinguishes strong from weak convection events. Additionally, we identify “dawn-dominant” events characterized by primary SML enhancements in the dawn sector as a separate category. “Strong convection” events feature stronger and longer southward IMF and faster solar wind speeds than “weak convection” events. “Dawn-dominant” events share similar conditions with the “strong convection” category plus a tendency of negative <i>B</i>_y. “Strong convection” events statistically have lower onset magnetic latitudes (MLAT), indicating current sheet instabilities closer to the Earth. Field-aligned current (FAC) evolution reveals that the two-cell convection pattern extends from dayside to nightside before onset, possibly contributing to flux depletion and current sheet thinning. An event with strong convection exhibits continued pressure loading, with unloading occurring only after onset. This indicates a significant contribution of open flux accumulation to current sheet thinning. The example dawn-dominant event has strong global convection dominating the SMU/L profile, and aurora are brightened in a wide MLT range. On top of this, localized bursts in SML, aurora, dipolarizations, and flux ropes suggest that meso-scale current sheet disturbances occur. These classifications and analyses help clarify how convection and current sheet disturbances develop and interact, potentially valuable for elucidating the descriptions of substorm processes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can Solar Cyclic Variability Mimic Extreme Solar Particle (Miyake) Events in Radiocarbon?","authors":"Ilya Usoskin,&nbsp;Fusa Miyake,&nbsp;Kseniia Golubenko","doi":"10.1029/2026JA035427","DOIUrl":"https://doi.org/10.1029/2026JA035427","url":null,"abstract":"<p>Rapid, strong enhancements in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Δ</mi>\u0000 <mn>14</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${{Delta }}^{14}$</annotation>\u0000 </semantics></math>C in the Earth's atmosphere, known as Miyake events, rarely occurred over the past millennia, pointing to major radiation storms affecting Earth. They are produced by extreme solar particle events (ESPEs) and are separated by an order-of-magnitude gap in the strength from directly observed solar particle storms. This leaves their physical interpretation unconstrained. To bridge this gap, weak–moderate Miyake events ought to be detected, but this possibility was previously limited by the accuracy of individual ¹⁴C measurements. Here, we performed a sensitivity study of the detectability of a Miyake event in radiocarbon data over the background of natural <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Δ</mi>\u0000 <mn>14</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${{Delta }}^{14}$</annotation>\u0000 </semantics></math>C variability. The study was done for realistic conditions, including a reference ESPE, using the SOCOL:14C-Ex (SOlar CLimate Ozone Links model, radiocarbon version for extreme solar proton events) model of carbon transport in the Earth's atmosphere. We found that background variability, such as long-term trends and the solar cycle, can significantly distort and even mimic weak-to-moderate Miyake events in radiocarbon data. We conclude that reducing measurement errors alone is not sufficient to identify such weaker events. In addition, the galactic cosmic ray (GCR)-related background should be reconstructed over ≈50 years around event candidates using high-precision annual measurements of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Δ</mi>\u0000 <mn>14</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${{Delta }}^{14}$</annotation>\u0000 </semantics></math>C.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JA035427","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inward Radial Decay of Magnetopause Perturbations","authors":"S. Abaidoo,&nbsp;D. G. Sibeck","doi":"10.1029/2026JA035288","DOIUrl":"https://doi.org/10.1029/2026JA035288","url":null,"abstract":"<p>Theory predicts that the magnetic field strength perturbations produced by the Kelvin-Helmholtz instability decay exponentially with distance inward from the magnetopause but that the perturbations generated by isolated cylindrical indentations on the magnetopause (e.g., flux transfer events or FTEs) decay as the inverse square of the distance from the magnetopause. By contrast, global magnetohydrodynamic simulations indicate that planar density fronts in the solar wind produce perturbation amplitudes that initially decay with inward radial distance from the magnetopause but then increase with further distance inward due to the superposition of incident and reflected fast mode compressional waves. Time History of Events and Macroscale Interactions during Substorms A–E magnetic field strength observations from 0000 to 0500 UT on 31 July 2007 within the subsolar magnetosphere confirm the inward propagation of perturbations whose peak amplitude and standard deviation decay rapidly with distance from the magnetopause. Solar wind, magnetosheath, and magnetospheric observations suggest an interpretation of the perturbations in terms of boundary ripples driven by solar wind pressure perturbations.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Detailed Temporal Characterization of Equatorial Plasma Irregularities Using MultiBaseline Spaced Receiver Scintillation Measurements From Geostationary Satellites","authors":"K. M. Ambili,&nbsp;D. V. P. Krishna,&nbsp;R. K. Choudhary","doi":"10.1029/2025JA034953","DOIUrl":"https://doi.org/10.1029/2025JA034953","url":null,"abstract":"<p>We investigated the temporal evolution of ionospheric irregularities over the equatorial F-region (above 200 km) that generates after local sunset using the spaced-receiver technique to monitor scintillation patterns in the L1 signal from geostationary satellites. Three receivers, spaced 40 and 100 m apart, were deployed along the magnetic east-west direction to estimate the time lags between scintillation patterns and to derive the zonal drift velocity of plasma structures. At the onset of scintillation events, the drift velocity reached up to ∼180 m/s, gradually decreasing to about 40 m/s. Power spectral analysis revealed spectral slopes of around −3 during peak scintillation periods, indicating a rapid energy cascade. The scale sizes of the irregularities were estimated to be ∼800 m at the time of their formation, cascading to ∼200 m as the event progressed. These results provide the first detailed characterization of the temporal evolution of plasma irregularities at the dip equator in the Indian sector using geostationary satellites, offering new insights into equatorial ionospheric dynamics.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multi-Event Comparison of dB/dt Resulting From Omega Band Aurora","authors":"R. M. Hodnett,&nbsp;S. E. Milan,&nbsp;S. K. Vines,&nbsp;J. W. Gjerloev,&nbsp;L. J. Paxton","doi":"10.1029/2026JA035740","DOIUrl":"https://doi.org/10.1029/2026JA035740","url":null,"abstract":"<p>Omega bands are an auroral form occurring in the dawn sector which cause magnetic perturbations on the ground as they drift eastwards. If these changes in the magnetic field are large, omega bands can become a space weather hazard as the corresponding geomagnetically induced currents have the potential to cause damage to ground based infrastructure. In this study we analyze three intervals of omega band activity which have varying values of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>d</mi>\u0000 <mi>B</mi>\u0000 <mo>/</mo>\u0000 <mi>d</mi>\u0000 <mi>t</mi>\u0000 </mrow>\u0000 <annotation> $mathrm{d}B/mathrm{d}t$</annotation>\u0000 </semantics></math> in order to gain more insight into why some omega band events may be more hazardous than others. The event with the largest <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>d</mi>\u0000 <mi>B</mi>\u0000 <mo>/</mo>\u0000 <mi>d</mi>\u0000 <mi>t</mi>\u0000 </mrow>\u0000 <annotation> $mathrm{d}B/mathrm{d}t$</annotation>\u0000 </semantics></math> of greater than 500 nT <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>min</mtext>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{min}}^{-1}$</annotation>\u0000 </semantics></math> occurred during a prolonged period of southward interplanetary magnetic field. The larger changes in magnetic field during this omega band event resulted because the ionospheric convection speed was greater, which means larger drift speeds of the omega bands and their associated current structures. When investigating the current structures in more detail, we found that omega band signatures are visible in AMPERE data, confirming that they are located in the region 1 region 2 current boundary. We also report that as well as electron aurora, omega bands have proton aurora which maps to the same location as the electron aurora in the dawn sector. This observation indicates that there is an intricate current structure in the dawn sector.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JA035740","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148785198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peculiar Magnetosphere-Atmosphere Coupling and Its Impacts Over the South American Magnetic Anomaly Region","authors":"Lígia A. Da Silva,&nbsp;Hui Li,&nbsp;Laysa C. A. Resende,&nbsp;Vânia F. Andrioli,&nbsp;Angela M. Santos,&nbsp;Juliano Moro,&nbsp;Paulo R. Jauer,&nbsp;Luis Eduardo Vieira,&nbsp;Lívia R. Alves,&nbsp;José Paulo Marchezi,&nbsp;Jiankui Shi,&nbsp;Jiyao Xu,&nbsp;Paulo P. Batista,&nbsp;Jose V. Bageston,&nbsp;Yajun Zhu,&nbsp;Clezio M. Denardini,&nbsp;Chi Wang,&nbsp;Ezequiel Echer,&nbsp;Guotao Yang,&nbsp;Alexandre A. Pimenta,&nbsp;Joaquim R. Costa,&nbsp;Zhengkuan Liu","doi":"10.1029/2026JA035200","DOIUrl":"https://doi.org/10.1029/2026JA035200","url":null,"abstract":"<p>The auroral-like sporadic E-layer is typically observed at altitudes between 100 and 150 km within the South American Magnetic Anomaly region. However, the occurrence of an unusual layer event detected above this altitude range on 18 July 2017 has raised intriguing questions regarding the physical processes responsible for the substantial vertical displacement of this layer. The interplanetary medium conditions during the event exhibited characteristics consistent with the recovery phase of a geomagnetic storm driven by a complex solar wind structure, occurring after substorm activity. To address this atypical layer occurrence, we examined the magnetospheric conditions using the BATS-R-US model with two experiments: one including the actual geomagnetic dipole inclination and another omitting it. These configurations allow for a discussion of the energy deposition processes under the prevailing interplanetary medium conditions. Also, the dynamics of the inner radiation belt were investigated through analysis of the magnetic field power spectral density and low-energy electron flux measurements from the Van Allen Probes mission to verify electron precipitation. Plasma wave observations and their characterization also revealed atypical behavior, in which a non-standard confinement of hiss waves (200 and 500 Hz) occurred simultaneously with an electron flux decrease (&lt;1 keV), an integrated ionization rate between 250 and 300 km, and the formation of a peculiar layer. Finally, although this magnetic storm was moderate, we demonstrate that particle precipitation significantly impacted the atmosphere, as evidenced by pronounced ozone depletion in the mesosphere with magnitudes substantially stronger when compared to the extreme storm of May 2024.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JA035200","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theta Aurora: Transpolar Arcs Linked to a Folded Magnetotail Neutral Sheet","authors":"S. C. Hill,&nbsp;T. I. Pulkkinen,&nbsp;A. Kullen,&nbsp;A. Brenner,&nbsp;M. Ala-Lahti,&nbsp;Q. Al Shidi,&nbsp;A. Mukhopadhyay,&nbsp;S. Zou,&nbsp;M. Liemohn,&nbsp;A. N. Jaynes","doi":"10.1029/2025JA034825","DOIUrl":"https://doi.org/10.1029/2025JA034825","url":null,"abstract":"<p>Nightside-originating transpolar arcs (TPAs) represent a distinct mechanism of magnetosphere-ionosphere energy transfer during northward IMF conditions. Nightside-originating TPAs originate from the nightside auroral oval and grow across the polar cap to connect to the dayside, appearing to cross multiple topological boundaries as they develop. We study the magnetospheric conditions required for such a phenomenon by modeling the 10 January 1997 nightside-originating TPA event observed by Polar UVI with a high resolution SWMF Geospace simulation. Our simulation produces a large central fold in the magnetotail neutral sheet that protrudes into the northern lobe. When magnetically mapped into the ionosphere, the development and subsequent dynamics of the folded neutral sheet show remarkable agreement to the observed nightside-originating TPA. The folded neutral sheet bifurcates the northern lobe in the mid-tail, around <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>X</mi>\u0000 <mo>=</mo>\u0000 <mo>−</mo>\u0000 <mn>30</mn>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>E</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> $X=-30{R}_{E}$</annotation>\u0000 </semantics></math>, and is located within a region of field-aligned current (FAC) generation. We suggest that the large central fold in the neutral sheet forms as a response to multiple opposing twists of the magnetotail, driven by the changes in the IMF <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>B</mi>\u0000 <mi>Y</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${B}_{Y}$</annotation>\u0000 </semantics></math> direction. We discuss the formation and decay of the neutral sheet fold during northward and southward IMF, and the relationship of the neutral fold to the ionospheric convection. Our results suggest that a neutral sheet fold with subsequent FAC generation is needed for transpolar arc activity, rather than just an extended closed field line region poleward of the main auroral oval.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of Ionospheric Conductance During the December 2021 Solar Eclipse on the Coupled Magnetosphere-Ionosphere-Thermosphere System","authors":"Yu Hong,&nbsp;Yue Deng,&nbsp;Daniel T. Welling,&nbsp;Aaron J. Ridley,&nbsp;Gang Lu,&nbsp;Astrid Maute,&nbsp;Qingyu Zhu,&nbsp;Sebastijan Mrak,&nbsp;Colin Waters,&nbsp;Cheng Sheng,&nbsp;Minjing Li,&nbsp;Ramon Lopez","doi":"10.1029/2026JA035392","DOIUrl":"https://doi.org/10.1029/2026JA035392","url":null,"abstract":"<p>Solar eclipses provide unique opportunities to investigate geospace dynamics driven by rapid, localized reductions in solar radiation. On December <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>4</mn>\u0000 <mtext>t</mtext>\u0000 <mtext>h</mtext>\u0000 </mrow>\u0000 <annotation> $4text{t}text{h}$</annotation>\u0000 </semantics></math>, 2021, a total solar eclipse occurred over West Antarctica during substorms. While eclipse effects on Earth's upper atmosphere are widely studied, their subsequent impact on the magnetospheric configuration and feedback loops are less explored. Abrupt changes in conductivity can also affect interhemispheric asymmetry (IHA). In this study, an eclipse EUV mask was applied in the Global Ionosphere-Thermosphere Model (GITM), driven by different high-latitude forcing specifications. Using the Space Weather Modeling Framework, we examined how eclipse-induced ionospheric conductance changes impact the magnetosphere and feed back to the I-T system. Results show a −∼30% reduction in total electron content and −∼35% drop in ionospheric conductance compared to the no-eclipse case, consistent with observations. This leads to an enhanced cross-polar cap potential (CPCP) in both hemispheres (north vs. south: 36 vs. 40 kV). The eclipse reduced IHA in total field-aligned currents and CPCP, bringing asymmetry close to zero after the shadow passed over the polar region. The magnetosphere also showed dynamic responses, including changes in plasma pressure and flow that shifted the magnetotail by up to 16 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>E</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${R}_{E}$</annotation>\u0000 </semantics></math> in the <i>X</i>-direction. Finally, by driving GITM with eclipse-modified magnetospheric forcing, we found that magnetospheric feedback amplified thermospheric wind perturbations over the polar cap, even exceeding the direct effect of reduced solar EUV. These results demonstrate the critical role of ionospheric conductance in the coupled M-I-T system during solar eclipses.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JA035392","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-Term Influence of Solar Wind Dynamics on Earth's Geomagnetic Activity","authors":"Ziyadat Hassan,&nbsp;Zamri Zainal Abidin,&nbsp;Affan Adly Nazri,&nbsp;Indriani Sukma,&nbsp;Zhihao Hou,&nbsp;Ahmad Najwan Zulkiplee,&nbsp;Mohd Shazwan Mohd Radzi,&nbsp;Jinsong Ping,&nbsp;Liang Dong","doi":"10.1029/2026JA035147","DOIUrl":"https://doi.org/10.1029/2026JA035147","url":null,"abstract":"<p>Sunspot-based indices are widely used to describe solar activity but do not directly quantify the energy transferred from the solar wind into the near-Earth space environment that drives geomagnetic variability on long timescales. We examine the long-term influence of solar wind dynamics on Earth's geomagnetic activity using nearly five decades of OMNI observations spanning solar cycles 21–25 (1976–2025). Key solar wind parameters, geomagnetic indices (Dst and AE), and a physically motivated solar wind input energy (SWIE) coupling function are analyzed to assess their statistical relationships and solar-cycle dependence. Geomagnetic activity is found to be only weakly correlated with the sunspot number, but strongly associated with heliospheric drivers, particularly solar wind speed, interplanetary magnetic field properties, and SWIE. The AE index shows greater sensitivity to solar wind forcing than Dst, especially during declining solar-cycle phases dominated by high-speed streams. Spectral analysis reveals a clear ∼11-year periodicity in SWIE, lagging the sunspot cycle by an average of ∼8 months. Comparative evaluation against alternative coupling functions (Akasofu, Newell, and McPherron) demonstrates that SWIE uniquely retains robust solar-cycle periodicity and strong geomagnetic correlations at monthly, cycle-relevant cadences. These results highlight SWIE as a physically grounded, robust alternative indicator of long-term solar-cycle variability.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"131 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}