Journal of Geophysical Research: Space Physics最新文献

{"title":"A New Fast Calculation Method for Pedersen and Hall Conductances From Maxwellian Electron Precipitation: Incorporating Magnetic Field Dependence","authors":"Xiaohua Fang","doi":"10.1029/2025JA033835","DOIUrl":"https://doi.org/10.1029/2025JA033835","url":null,"abstract":"<p>Accurate and efficient calculation of ionospheric conductances from electron precipitation is crucial for large-scale magnetosphere-ionosphere coupling studies. Early parameterization models, derived from simplistic particle transport calculations under very limited background conditions, suffered from significant uncertainties. To address these limitations, we systematically compute electron impact effects under nearly 2 million diverse background scenarios, encompassing variations in geomagnetic field strength and atmospheric conditions. These scenarios are generated by varying geographic location, solar and geomagnetic activity, local time, and season. From these calculations, we derive altitude-dependent Pedersen and Hall conductivities, which are integrated over height to yield conductances. Our results show that ionospheric conductances depend not only on precipitation characteristics but also strongly on the local background geomagnetic field strength, which can lead to several-fold variations in conductances under identical precipitation conditions. This finding highlights the importance of accounting for geomagnetic field spatial variations when constructing global conductance distributions. To enable efficient application of these results, we develop a parameterization for Maxwellian electron precipitation with average energies of 1–20 keV, achieving fitting errors within <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math>5%, a substantial improvement over earlier models with discrepancies ranging from <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>75</mn>\u0000 </mrow>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${-}75$</annotation>\u0000 </semantics></math>% to 25%. Furthermore, we show that average energy alone is insufficient to characterize precipitation conditions. Differences in spectral shapes, even at the same average energy, can produce order-of-magnitude variations in conductances, particularly for Hall conductance at low energies. This work provides both a robust tool for global applications and new insights into ionospheric conductance variability.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758657","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":"Global Seasonal Variations of Martian Atmospheric Pressure and Density From Mars Climate Sounder","authors":"Zhaopeng Wu,&nbsp;Tao Li,&nbsp;Jun Cui,&nbsp;Chengyun Yang,&nbsp;Zhaojin Rong,&nbsp;Fei He,&nbsp;Jing Li,&nbsp;Xuan Cheng,&nbsp;Yong Wei","doi":"10.1029/2025JA034148","DOIUrl":"https://doi.org/10.1029/2025JA034148","url":null,"abstract":"<p>Pressure and density are fundamental atmospheric parameters that reflect the mass and thermodynamic structure of the planetary atmosphere. They have a complex spatial distribution and dramatic seasonal variations in the cold, CO₂-dominated Martian atmosphere. However, their seasonal variations on global scales and their quantitative correlations with atmospheric mass, thermal structure and dust activity have not been systematically analyzed. This study uses remotely sensed data from the Mars Climate Sounder to investigate the spatial and temporal variations of the complex Martian atmospheric pressure and density in a global view from the surface to the mesosphere. In the vertical direction, changes in atmospheric pressure and density above 40 km are largely influenced by expansion or contraction effects of the Martian atmosphere in response to annual changes in solar radiation intensity and dust loading, while the atmosphere in the lower 20 km is more sensitive to semiannual variations in total atmospheric mass related to the evolution of the polar ice caps. To quantify the influence of large dust storms on the thermal structure and mesospheric density structure, we applied correlation analysis and found the best correlations for 90-km density, 35-km temperature and 23-km dust. Finally, the quantitative linear relationships between the three are established, which can provide simplified and readily applicable empirical relationship constraints for future modeling studies of the lower thermosphere below 200 km. This is important for future analyses of the upper atmospheric response to dust storms, and also useful for improving the aerobraking design of future Mars exploration missions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144764117","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":"Latitudinal Evolution of the Quasi-5-Day Waves During the 2021 Arctic Sudden Stratospheric Warming Event","authors":"Jiaxin Bao,&nbsp;Zheng Ma,&nbsp;Yun Gong,&nbsp;Shaodong Zhang,&nbsp;Chunming Huang,&nbsp;Junfeng Yang,&nbsp;Dan Liu","doi":"10.1029/2025JA033969","DOIUrl":"https://doi.org/10.1029/2025JA033969","url":null,"abstract":"<p>Using observations from a meteor radar chain, the Aura satellite, and reanalysis data, this study investigates the characteristics of quasi-5-day waves (Q5DWs) in the mesosphere and lower thermosphere (MLT) region of the Northern Hemisphere during the January 2021 Arctic sudden stratospheric warming (SSW) event. After the SSW onset, westward-propagating Q5DWs were detected in the MLT region at Mohe (53.5°N), Beijing (40.3°N), Wuhan (30.5°N), and Ledong (18.3°N). Hough function calculation and satellite observations reveal that the Q5DWs observed in meteor radar winds at Mohe and Beijing consist of both westward wavenumber 1 (W1) and westward wavenumber 2 (W2) components, whereas the W1 component dominates at Wuhan and Ledong. The key findings of this study include: (a) both meteor radar and satellite observations identified the weakest Q5DW activity at low latitudes during the SSW event, and (b) in addition to a mesospheric wave source for W1 and W2 components around 55°N, an additional mesospheric wave source for the W1 component around 35°N was identified, likely contributing to its broader latitudinal coverage compared to the W2 component. These results offer valuable insights into the latitudinal evolution of Q5DWs in the MLT region during SSW events.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144764118","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":"Modeling MSTIDs Produced by Gravity Waves With Parameters Obtained From All-Sky Imager Observations and Comparisons to Incoherent Scatter Radar Observations","authors":"Harold K. Knight,&nbsp;Philip G. Richards,&nbsp;Carlos R. Martinis,&nbsp;Larisa P. Goncharenko","doi":"10.1029/2025JA033906","DOIUrl":"https://doi.org/10.1029/2025JA033906","url":null,"abstract":"<p>Hypotheses concerning processes related to medium-scale traveling ionospheric disturbances (MSTIDs) are investigated with the application of models and the analysis of observational data. Wave-packet parameters for MSTIDs from 2011 through 2022 are obtained from OI 6300 Å observations from the Boston University all-sky imager (ASI) at the Millstone Hill Observatory during periods for which concurrent Millstone Hill (MH) incoherent scatter radar (ISR) observations are available. A combination of a numerical multi-layer (NML) model for gravity waves (GW) in the thermosphere with the Field-Line Interhemispheric Plasma (FLIP) model for ionospheric processes and upper-atmospheric emissions is applied to generate perturbation electron-density values, which are compared with ISR-observed perturbation electron-density values. A detailed comparison is made between model-generated and ISR-observed electron density for two cases, and the comparisons show notably good agreement. Twelve other MSTID cases are also described, giving a total of 14 cases. The results confirm that some nighttime MSTIDs at midlatitudes directly correspond to local GWs. They also suggest that some MSTIDs occurring over MH primarily consist of plasma fluctuations without corresponding local neutral fluctuations and that such MSTIDs are more common during winter months. The phase relationship between electron density and neutral vertical velocity variations is examined for two cases. Additionally, the hypothesis that standard thermospheric dynamic molecular viscosity values should be reduced is evaluated, and it is found that this is not supported by the results.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758659","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":"IMAGE Satellite and Ground-Based Magnetometer Observations of Large Geomagnetic Disturbances and Rapid Variations in Ionospheric and Vertical Currents","authors":"Mark J. Engebretson,&nbsp;Stephen B. Mende,&nbsp;James M. Weygand,&nbsp;Ethiopia H. Kebede,&nbsp;Jesus A. Ochoa,&nbsp;Sheng Tian,&nbsp;Erik S. Steinmetz,&nbsp;Mark B. Moldwin,&nbsp;Michael D. Hartinger,&nbsp;Chigomezyo M. Ngwira,&nbsp;Jesper W. Gjerloev","doi":"10.1029/2025JA033769","DOIUrl":"https://doi.org/10.1029/2025JA033769","url":null,"abstract":"<p>Ultraviolet images of Earth's polar regions obtained by high altitude spacecraft have proved to be immensely useful for documenting numerous features of the aurora and understanding the coupling between Earth's magnetosphere and ionosphere. In this study we have examined images obtained by the far ultraviolet Spectrographic Imager camera on the IMAGE satellite during the first three years of its mission (2000–2002) for comparison with observations of large geomagnetic disturbances (GMDs) by ground-based magnetometers in eastern Arctic Canada. To our knowledge, this is the first study to investigate the use of high-altitude imager data to identify the global context of GMDs. We found that rapid auroral motions or localized intensifications visible in these images coincide with regions of large <i>dB</i>/<i>dt</i> as well as localized and closely spaced up/down vertical currents and increased equivalent ionospheric currents, but one of the two events presented did not appear to be related to substorm processes. These magnetic perturbations and currents can appear or disappear in a few tens of seconds, thus highlighting the importance of images with a high cadence.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716539","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":"Atmospheric Mass Flux as a Function of Ionospheric Emission on Unmagnetized Earth","authors":"P. C. Hinton,&nbsp;D. A. Brain,&nbsp;N. R. Schnepf,&nbsp;R. Jarvinen,&nbsp;J. Cessna,&nbsp;F. Bagenal","doi":"10.1029/2024JA033663","DOIUrl":"https://doi.org/10.1029/2024JA033663","url":null,"abstract":"&lt;p&gt;We explore ion escape from, and solar ion deposition to, an unmagnetized Earth-like planet. We use RHybrid, an ion-kinetic electron-fluid code to simulate the global plasma interaction of unmagnetized Earth with the solar wind. We vary the global ionospheric emission rate, and quantify the resultant planetary ion escape rates (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${O}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${H}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and the solar wind deposition rate (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${H}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). We use these results to compute the net mass flux to the atmosphere and find that the solar ion deposition rate could be comparable to planetary ion escape rates. For the emission rates simulated, our results show that under typical solar wind conditions (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;400&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{sw}=400 mathrm{k}mathrm{m} {mathrm{s}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;5&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${n}_{sw}=5 mathrm{c}{ma","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716540","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":"Contamination Effects on Sweeping Langmuir Probes Onboard Sounding Rocket Flights: Understanding Through Simulation","authors":"Rachel Conway,&nbsp;Aroh Barjatya","doi":"10.1029/2025JA034058","DOIUrl":"https://doi.org/10.1029/2025JA034058","url":null,"abstract":"<p>Sweeping Langmuir Probes (SLP) are commonly used on sounding rocket platforms for <i>in situ</i> plasma density, electron temperature, and spacecraft charging/floating-potential measurements. The probe surfaces are often contaminated, typically evident through distortion of the measured Current-Voltage (IV) curve. This distortion is characterized by a separation between up and down sweeps (hysteresis), magnitude scaling, and a long-term charge accumulation across the contamination layer. Fast sweep rates are often implemented to bypass contamination, and a lack of hysteresis has been used as a qualitative metric for probe cleanliness. This practice is investigated using SPICE (Simulation Program with Integrated Circuit Emphasis), and simulation results are presented for a contaminated SLP onboard a sounding rocket. The results offer an in-depth, encompassing analysis of the effects of contamination on SLP's three major data products, as well as methods for mitigation appropriate for sounding rocket platforms.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716538","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":"Propagation Characteristics of Gravity Waves Around Critical Layers Revealed by the Andes Lidar","authors":"Ming Yu Hu,&nbsp;Shao Dong Zhang,&nbsp;Chun Ming Huang,&nbsp;Yun Gong,&nbsp;Kai Ming Huang,&nbsp;Zheng Ma","doi":"10.1029/2025JA033864","DOIUrl":"https://doi.org/10.1029/2025JA033864","url":null,"abstract":"<p>By analyzing horizontal wind and temperature data from the Andes Lidar Observatory Na lidar at Cerro Pachón, Chile (30.3°S, 70.7°W) from May 2014 to July 2019, we investigated the evolution process, propagation characteristics, and influencing factors of gravity waves (GWs) encountering the critical layer. Adopting the criterion that the critical layer is observed when the intrinsic frequency reaches 1.3 times the inertial frequency, accompanied by a sharp decrease in vertical wavelength, we identified 40 critical layer events, with an occurrence rate of 58.9%, indicating that critical layers are common phenomena in the MLT of the Andes mountain area. All observed GWs encountering the critical layer propagate along the wind, with rapid decreases in vertical wavelength and energy and momentum absorption by the background. When the critical layer appears, 44.2% of the wave energy is below 20 J/kg, and 30.4% of momentum flux is below 50 m²/s². Contrary to the predictions of linear theory, not all waves are fully absorbed at the critical layer. Some carry residual energy to higher altitudes until reaching a second (19.1%) or third (4.4%) critical layer. These effects must be considered in the future GWs parameterization models. The occurrence rate of critical layers shows significant seasonal and altitude variations, being higher in autumn and lower in summer, mainly at 90–91 km, influenced by background wind and thermal structure. The critical layer usually forms below the mesopause, and its occurrence is negatively correlated with mesopause altitude, as a smaller buoyancy frequency favors its formation.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681248","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":"Dawn-Dusk Morphology of Auroral Arcs in Substorm Growth Phase","authors":"Zepeng Liu,&nbsp;San Lu,&nbsp;Y. Nishimura,&nbsp;Quanming Lu,&nbsp;Boyi Wang,&nbsp;Yuzhang Ma,&nbsp;Zhibo Zhang,&nbsp;Rongsheng Wang,&nbsp;Rajkumar Hajra,&nbsp;S. Apatenkov,&nbsp;E. Grigorenko,&nbsp;A. V. Artemyev,&nbsp;V. Angelopoulos","doi":"10.1029/2025JA033860","DOIUrl":"https://doi.org/10.1029/2025JA033860","url":null,"abstract":"<p>The substorm growth phase plays a critical role in magnetospheric energy storage through magnetotail plasma sheet thinning and magnetic flux loading, and the study of auroral morphology and structure helps us understand the process of magnetotail energy accumulation and release. This study focuses on quiescent auroral arcs, which characterizes the growth phase of substorms and precedes the subsequent expansion thereon; we utilize the observational data from Time History of Events and Macroscale Interactions (THEMIS) all-sky imagers and obtain 47 substorm growth phase arcs from 2014 to 2022. We find that the auroral arcs typically maintain structural stability, and most of them (∼72.3%) move equatorward in the growth phase during which a latitudinal minimum is recorded on the duskside. Statistical examination of the 47 distinct substorm events confirms this dawn-dusk asymmetry in growth phase arc distribution. Such morphology of the growth phase arcs may originate from the magnetotail current sheet that is thinner on the duskside, we propose that this morphological characteristic likely reflects the dusk-favored magnetotail current sheet thinning process, constituting a systematic duskside preference in magnetospheric dynamics that may originate from the interplay between solar wind-magnetosphere coupling and the Hall current system in the magnetotail.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144688099","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":"Morphological Study of Plasma Bubbles Using All-Sky Airglow Images and Numerical Simulations: Brazilian Sector","authors":"A. J. Carrasco,&nbsp;C. M. Wrasse,&nbsp;H. Takahashi,&nbsp;I. S. Batista,&nbsp;D. Barros,&nbsp;C. A. O. B. Figueiredo,&nbsp;J. R. Souza,&nbsp;L. V. Peres,&nbsp;R. Silva","doi":"10.1029/2025JA033934","DOIUrl":"https://doi.org/10.1029/2025JA033934","url":null,"abstract":"<p>This study meticulously examines the morphology of ionospheric plasma depletions, or bubbles, using OI 630 nm airglow all-sky images captured over three Brazilian observatories: Santarém, Bom Jesus da lapa, and Cariri. The analysis focuses on key morphological parameters: zonal distance between adjacent bubbles (Xd), base width of the bubbles (Xw), and branch separation in bifurcated bubbles (Xr). Santarém, the newest equatorial observatory, revealed consistent, periodic depletion aligned with the magnetic meridian, with a peak of 17 bubbles observed in a single night. Conversely, Cariri and Bom Jesus da Lapla exhibited more complex structures, including bifurcations and ramifications. A statistical analysis of 60 nights revealed that Xd ranged from 69 to 214 km, Xw from 24 to 67 km, and Xr from 98 to 269 km. Notably, the zonal distance (Xd), linked to the perturbation seed wavelength (<i>λ</i>) in the equatorial F region, showed no dependence on solar flux. However, both Xw versus Xd and Xr versus Xw displayed strong linear correlation exceeding 80%. To further investigate these findings, a novel three-dimensional bubble model SUPIM/PBM3D, was developed. The theoretical results from this model showed good agreement with the observed airglow morphology, validating the empirical findings and providing a deeper understanding of the processes governing plasma bubble formation and evolution.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033934","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681246","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}