Journal of Geophysical Research: Space Physics最新文献

{"title":"Interplanetary Hydrogen Observations of the Emirates Ultraviolet Spectrometer Onboard the Emirates Mars Mission","authors":"R. Susarla,&nbsp;J. Deighan,&nbsp;M. S. Chaffin,&nbsp;E. Quemerais,&nbsp;S. Jain,&nbsp;R. J. Lillis,&nbsp;G. Holsclaw,&nbsp;K. Chirakkil,&nbsp;D. Brain,&nbsp;Ed. Thiemann,&nbsp;F. Eparvier,&nbsp;F. Lootah,&nbsp;M. Gacesa,&nbsp;M. O. Fillingim,&nbsp;J. S. Evans,&nbsp;H. AlMazmi,&nbsp;H. AlMatroushi,&nbsp;M. R. El-Maarry","doi":"10.1029/2025JA033903","DOIUrl":"https://doi.org/10.1029/2025JA033903","url":null,"abstract":"<p>The Emirates Mars Ultraviolet Spectrometer (EMUS) aboard the Emirates Mars Mission (EMM) has been studying backscattered interplanetary hydrogen (interplanetary hydrogen (IPH)) Lyman emissions with dedicated observation strategies viz., U-OS3b and U-OS4b. These observation techniques involve looking away from Mars from the EMM's orbit. U-OS3b provides broader coverage of the Martian sky, while U-OS4b is designed to achieve high signal-to-noise measurements. Here we present analysis of the interplanetary hydrogen emission distribution across the sky, particularly at the Lyman-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 <annotation> $alpha $</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 </mrow>\u0000 <annotation> $beta $</annotation>\u0000 </semantics></math> emission wavelengths. EMUS observes a well-known reduction in the brightness of interplanetary hydrogen as the observation angle increases across the sky from the hydrogen bulk flow upwind direction. Our modeled emission intensities indicate that when Mars is around aphelion, the observed emissions are dominated by IPH rather than Martian exospheric hydrogen. Our modeled intensities for H Ly-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 <annotation> $alpha $</annotation>\u0000 </semantics></math> emission are smaller by a factor of 1.6 compared to the observations, and they are consistent with the observations for H Ly-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 </mrow>\u0000 <annotation> $beta $</annotation>\u0000 </semantics></math> emission. The H Ly-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 <annotation> $alpha $</annotation>\u0000 </semantics></math> intensities measured by the Imaging Ultraviolet Spectrograph (IUVS) on board the Mars Atmosphere and Volatile EvolutioN mission were found to be 45% lower than those from EMUS measurements, likely owing to differences in the instruments' calibration factors. During the observation period, differences in the measured intensities between the Solar Wind ANisotropy (SWAN) instrument aboard the Solar and Heliospheric Observatory and EMUS were also found to vary. These discrepancies can be attributed not only to instrumental factors but also to the relative positions of Earth and Mars.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033903","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331991","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":"Parametric Regimes of Thin Current Sheets in Planetary Magnetospheres and Solar Wind","authors":"David S. Tonoian,&nbsp;Xiao-Jia Zhang,&nbsp;Anton Artemyev,&nbsp;Qianli Ma,&nbsp;Robert W. Ebert,&nbsp;Frederic Allegrini","doi":"10.1029/2025JA033942","DOIUrl":"https://doi.org/10.1029/2025JA033942","url":null,"abstract":"<p>Current sheets are quasi-1D layers of strong current density, which play a crucial role in storing magnetic field energy and subsequently releasing it through charged particle acceleration and plasma heating. They are observed in planetary magnetospheres and solar wind flows, where they are also known as solar wind discontinuities. Despite significant variations in plasma parameters across different magnetospheres and the solar wind, current sheet configurations can remain fundamentally similar. In this study, we analyze current sheets observed in various regions, including the near-Earth (within 30 Earth radii) and distant (50–200 Earth radii) magnetotail, Earth's dayside and nightside magnetosheath, the near-Earth solar wind, and Martian and Jovian magnetotails. We examine three key plasma parameters: the plasma beta (ratio of plasma to magnetic pressure), the Alfvénic Mach number (ratio of plasma bulk flow speed to Alfvén speed in the current sheet reference frame), and the ion to electron temperature ratio. Additionally, we investigate the kinetic, thermal, and magnetic field energy densities. Our cross-system analysis demonstrates that the same current sheet configuration can exist across a very wide parametric space spanning multiple orders of magnitude. We also highlight the distinct plasma environments of the Martian and Jovian magnetotails, characterized by large populations of heavy ions, emphasizing their significance in comparative magnetospheric studies.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331999","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":"Joint Observations of Plasmapause Surface Waves and Giant Undulations in the Electron Aurora","authors":"Xin-Yu Ai,&nbsp;Jie Ren,&nbsp;Qiu-Gang Zong,&nbsp;Yi-Xin Hao,&nbsp;Zi-Jian Feng,&nbsp;Ting-Yan Xiang","doi":"10.1029/2025JA033878","DOIUrl":"https://doi.org/10.1029/2025JA033878","url":null,"abstract":"<p>After the onset of an intense storm-time substorm (the minimum AL <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>−2,400 nT) on 8 September 2017, both Van Allen Probes and ground stations observed large-amplitude plasmasphere surface waves (PSWs) in the duskside, which lasted for more than 3 hr. Van Allen Probe B observations show that PSWs caused spatial and temporal modulations of sub-keV electrons with bidirectional pitch-angle distributions and higher-frequency plasma waves outside the plasmapause at the L-shells of 3.5–5.5. These kinetic-scale waves include kinetic Alfvén waves (KAWs) with frequencies below 10 Hz, time domain structures with frequencies from tens to hundreds of Hz, and electrostatic electron cyclotron harmonic waves (ECHs) with frequencies of tens of kHz. The bidirectional pitch angles and flux enhancement of sub-keV electrons indicate that they originate from the ionospheric outflow and are susceptible to pitch-angle scattering by kinetic-scale plasma waves. Following Probe B with a time delay of about 2 hr, Probe A observed PSW-associated ULF waves inside the plasmasphere at L-shells of 5–6, which can cause the drift-bounce resonance of cold (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>50 eV) electrons. Corresponding to the duration and location of PSWs, DMSP-F17 observed intense sub-keV electron precipitation and weak ion precipitation, which coincides with the observations of giant undulations (GUs) in the electron aurora. These space-ground joint observations provide new sights into understanding the complicated middle processes between magnetospheric PSWs and ionospheric GUs.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144332000","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":"Bipolar Reversal in the Off-Diagonal Ion Pressure Term in Collisionless Magnetic Reconnection","authors":"Kailai Wang,&nbsp;Lei Dai,&nbsp;Shan Wang,&nbsp;Yong Ren,&nbsp;Minghui Zhu,&nbsp;Chi Wang,&nbsp;Benoit Lavraud,&nbsp;C. Philippe Escoubet,&nbsp;James L. Burch","doi":"10.1029/2025JA034185","DOIUrl":"https://doi.org/10.1029/2025JA034185","url":null,"abstract":"<p>Magnetic reconnection is a fundamental process that converts magnetic energy into particle energy, with wide applications in space plasmas. A key manifestation of this energy conversion is the acceleration of fast ion outflows. However, ion processes and their associated signatures in energy conversion remains only partially understood in collisionless magnetic reconnection. In this study, we utilize statistical analyses of in-situ observations and particle-in-cell (PIC) simulations to identify a distinct signature in the off-diagonal component of the ion pressure tensor. This signature displays a bipolar reversal that correlates with ion outflows across the reconnection X-line. The bipolar signal originates from distorted ion velocity distributions during acceleration. These signals are confirmed by statistical in-situ evidence for the first time and captured by PIC simulations. PIC simulations further indicate the peak of the off-diagonal ion pressure is near the magnetic pileup region associated with the ion outflow. Trajectories of ions in the distorted velocity distributions are traced within the PIC simulations. Ions in the distorted distributions undergo partial cyclotron motion around the reconnected magnetic field (<i>B</i>_<i>z</i>) and acceleration by the reconnection electric fields. The observation of bipolar reversal in the off-diagonal ion pressure term indicate its spatial gradient, which could contribute to supporting ion-scale reconnection electric fields. These findings provide new insights into the fundamental features of energy conversion in collisionless magnetic reconnection.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315038","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":"Determining the Subsolar Magnetopause Position Using CMEM","authors":"S. J. Wharton,&nbsp;J. A. Carter,&nbsp;S. Sembay,&nbsp;Y. Soobiah,&nbsp;A. M. Read,&nbsp;T. R. Sun","doi":"10.1029/2025JA033837","DOIUrl":"https://doi.org/10.1029/2025JA033837","url":null,"abstract":"<p>The wide field-of-view soft X-ray imager on the upcoming SMILE mission will revolutionize our understanding of magnetopause dynamics from observations of SWCX in the magnetosheath. Inferring the position of the 3D magnetopause boundary in the 2D images is challenging, but several methods have been developed to do this. One method generates images through a 3D emissivity model and adapts its parameters to achieve the best fit with real images. The subsolar magnetopause position is extracted from the fitted model. We show that the Wharton et al. (2025, https://doi.org/10.1029/2024ja033307), cusp and magnetosheath emissivity model can be used successfully for this purpose in a wide range of scenarios. The method works when varying the image resolution, the orientation of the imager around its pointing axis, the aim point of the imager, and for a range of solar wind densities. We also show the method works from a range of orbital positions with realistically constrained viewing geometries. Finally, we tested the method on ensembles of realistic X-ray counts images which contain noise and instrumental contributions, allowing us to determine the uncertainty in the subsolar magnetopause distance over a wide range of solar wind densities. We found that CMEM accurately determined the subsolar magnetopause distance whenever it lies within the field-of-view and the signal-to-noise ratio was sufficient to observe the magnetosheath. The standard deviation of the subsolar magnetopause distance was less than 0.25 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>E</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${mathrm{R}}_{E}$</annotation>\u0000 </semantics></math> whenever the subsolar magnetopause was visible.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033837","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323573","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":"Geomagnetic Disturbances and Midlatitude Airglow During the 20 December 2015 Magnetospheric Storm","authors":"R. A. Marchuk,&nbsp;V. V. Mishin,&nbsp;Yu. V. Penskikh,&nbsp;Yu. Yu. Klibanova,&nbsp;A. V. Mikhalev","doi":"10.1029/2025JA033979","DOIUrl":"https://doi.org/10.1029/2025JA033979","url":null,"abstract":"<p>We report on the novel features of stormtime, midlatitude PiB/PiC geomagnetic pulsations, ionospheric and field-aligned currents, and oxygen, O¹S and O¹D, emissions at 557.7 and 630.0 nm, respectively. Those were observed during the main phase of the 20 December 2015 storm with significant variations of the solar wind dynamic pressure, <i>P</i>_<i>d</i>, and interplanetary magnetic field <i>B</i>_<i>z</i>. Intensifications of the shortest period, <i>Т</i> &lt; 10 s, Pi1B pulsations and oxygen emissions marked the substorm onsets. The distinct characteristic of the strong substorm (SME = 2,910 nT) was the presence of bay-like geomagnetic variations with the X and Z components with the opposite signs in the northern and southern sections of the IMAGE chain near 18 MLT. Using the magnetogram inversion technique of our institute, we obtained the MLT-MLAT distribution (map) of equivalent and field aligned currents revealing an additional westward electrojet to the north of the eastward current. We have shown that such a current system provides the observed distribution of geomagnetic variations along the 18 MLT meridian during the 20 December 2015 strong substorm, including at the high-latitude half of the IMAGE chain of stations. These conclusions were clearly validated by our simple current system model. We also revealed a localized geomagnetic event during the SME decrease interval between two substorm activations, when the magnitudes of the H/X geomagnetic component, PiB/PiC pulsations, and oxygen emissions at mid latitudes were more than twice greater than during the strong substorm.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315065","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":"Multifluid Equations for MHD","authors":"J. G. Lyon,&nbsp;V. G. Merkin,&nbsp;K. A. Sorathia,&nbsp;M. J. Wiltberger","doi":"10.1029/2025JA033884","DOIUrl":"https://doi.org/10.1029/2025JA033884","url":null,"abstract":"<p>A set of magnetohydrodynamic equations is developed for multiple ion species in the limit of small Larmor radius. The derivation proceeds to explicitly calculate the Lorentz force resulting from the small ion drift velocities. The net effect is that in this limit all the ions move perpendicular to the magnetic field with the same <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mi>E</mi>\u0000 <mo>×</mo>\u0000 <mi>B</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $mathbf{E}times mathbf{B}$</annotation>\u0000 </semantics></math> speed, but are free-streaming relative to one another in the parallel direction. The ions couple one to another in the parallel direction from changes in the magnetic field direction, leading to a collision-like term that, however, maintains a constant total kinetic energy. The equations governing parallel (centrifugal) acceleration, which may be an important process for ionospheric outflow, are then derived. The dispersion relation for a two-species, isotropic fluid with arbitrary mass and charge fractions, as well as electron pressure, is derived and the resulting wave modes are analyzed. A planar Alfvén mode separates from other, generally compressible, modes. It becomes unstable when the ram pressure of the streaming exceeds the firehose limit. The remaining modes satisfy a sixth order equation in the phase speed when counterstreaming and electron pressure are allowed. Without counterstreaming, three stable modes always exist, with two counter-propagating waves each, regardless of the presence of electron pressure. For the streaming case there are three modes, with two asymmetrically propagating waves each, whose behavior can be quite complicated, especially near the firehose instability limit. An example global magnetosphere simulation of a geomagnetic storm is presented using the derived multifluid formalism.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033884","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323572","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":"Modeling the Internal Redistribution of Earth's Proton Radiation Belt by Interplanetary Shocks","authors":"Alexander R. Lozinski,&nbsp;Adam C. Kellerman,&nbsp;Jacob Bortnik,&nbsp;Richard B. Horne,&nbsp;Ravindra T. Desai,&nbsp;Sarah A. Glauert","doi":"10.1029/2025JA033871","DOIUrl":"https://doi.org/10.1029/2025JA033871","url":null,"abstract":"<p>A large proton belt enhancement occurred on 24 March 1991 following an interplanetary shock that impacted the dayside magnetopause at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>03:40 UT. Its formation was measured by the proton telescope aboard CRRES and attributed to the injection and inward transport of solar energetic particles (SEPs) by an azimuthally propagating electric field pulse induced by the shock's compression of the magnetosphere. This led to an increase in the flux of high energy (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>25 MeV) protons by several orders of magnitude at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>≈</mo>\u0000 <mn>2.5</mn>\u0000 </mrow>\u0000 <annotation> $Lapprox 2.5$</annotation>\u0000 </semantics></math> which has been well-studied. However, a flux enhancement by up to one order of magnitude was also seen in 1–20 MeV protons at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>≈</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation> $Lapprox 2$</annotation>\u0000 </semantics></math>. Protons in this energy range pose a hazard to orbiting spacecraft as a major contributor to solar cell nonionizing dose. The 1–20 MeV enhancement cannot be explained by the inward transport of a solar proton source, because a newly injected source population at the required energy would have a drift velocity too low to interact with the pulse. Instead, we hypothesize that the 1–20 MeV enhancement was caused by the redistribution of radiation belt protons to different drift shells by the pulse. To test this hypothesis, we apply a novel method to predict the change in phase space density during a shock event which utilizes reverse-time particle tracing simulations. Our results show that the 1–20 MeV enhancement can be accounted for by internal redistribution as hypothesized. We thus identify a new mechanism for proton belt enhancements that does not depend on a SEP source and present a way to model it.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033871","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323574","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":"On Detection of Super Equatorial Plasma Bubbles in the American Sector During the 10–11 October 2024 Geomagnetic Storm","authors":"Irina Zakharenkova,&nbsp;Iurii Cherniak,&nbsp;Andrzej Krankowski,&nbsp;Cesar E. Valladares,&nbsp;Cesar De la Jara Sanchez","doi":"10.1029/2025JA033709","DOIUrl":"https://doi.org/10.1029/2025JA033709","url":null,"abstract":"<p>Multi-instrument analysis of ground-based and satellite observations (GNSS, ionosondes, magnetometers, Swarm, GOLD) revealed the formation of giant equatorial plasma bubbles (super-EPBs) in the American sector during the 10–11 October 2024 geomagnetic storm. Development of spectacular depletions, stretching between 30°N and 50°S (∼40°MLAT) across American continents with estimated apex altitudes of ∼3,500–4,000 km, was linked to storm-induced prompt penetration electric fields. Sudden southward turning of interplanetary magnetic field Bz component occurred at ∼22:40 UT, 10 October 2024, when the dusk sector reached western South America. Following a strong uplift of the ionosphere over Jicamarca/Peru by more than 400 km, the super-EPBs developed in this region, rapidly reaching midlatitudes. In the equatorial region, super-EPBs were confined to 65°–75°W longitudes. This fortunate localization gives a rare chance to trace super-EPB evolution near-entirely, from equatorial to middle latitudes in both hemispheres, due to extensive ground-based GNSS coverage. This allows us to unveil the complexity of super-EPB evolution with storm's progress: (a) Initial formation of post-sunset super-EPBs as field-oriented, inverted C-shape structures near 65°–75°W, (b) westward drift of outmost parts of these structures across midlatitudes from their original location, (c) formation of fresh post-midnight EPBs over the same locations as post-sunset EPBs, persisting until early morning. Ionosondes in North America midlatitudes (∼42°MLAT) registered rare observations of Spread-F associated with storm-induced EPBs. Strong amplitude scintillations were observed from sunset to sunrise. Super-EPBs bringing ionospheric irregularities and scintillations to unexpectedly high latitudes represent a perplexing phenomenon connecting physical processes across equatorial, middle and high latitudes during geomagnetic disturbances.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315330","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 Numerical Investigation of Equatorial Ionospheric Radial Currents During the Total Solar Eclipse on 29 March 2006","authors":"Hao Xia,&nbsp;Hui Wang,&nbsp;Kedeng Zhang","doi":"10.1029/2025JA033775","DOIUrl":"https://doi.org/10.1029/2025JA033775","url":null,"abstract":"<p>The solar eclipse is a common phenomenon, which produces significant disturbances in the ionosphere. Based on the CHAllenging Minisatellite Payload (CHAMP) observations and the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIEGCM) simulations, this work first investigates the responses of the Ionospheric Radial Currents (IRC) to the total solar eclipse on 29 March 2006. During the solar eclipse, IRC significantly enhanced inward. The intensity increased from −0.55 nA/m² at pre-eclipse to −3.97 nA/m² at eclipse, and ultimately recovered to −0.96 nA/m², yielding a structure similar to letter “V.” The TIEGCM simulations show that the inward IRC disturbance (ΔIRC) was dominated by the dynamo current (ΔDyn). During the eclipse period, the neutral temperature in the eclipse path was significantly decreased by the sunlight shadow. Above the dip equator, a westward local wind was generated, driving the F-layer dynamo and enhancing the inward ΔDyn. The inward ΔDyn at F-layer could separate the charged particles and generate the outward polarization electric field (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>Δ</mi>\u0000 <mi>E</mi>\u0000 </mrow>\u0000 <mi>z</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${{Delta }E}_{z}$</annotation>\u0000 </semantics></math>). This outward <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>Δ</mi>\u0000 <mi>E</mi>\u0000 </mrow>\u0000 <mi>z</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${{Delta }E}_{z}$</annotation>\u0000 </semantics></math> fed back to drive an outward polarization current (ΔPoL), modulating the density of ΔIRC. In addition, the Pedersen conductivity was suppressed by the upward movement of plasma at the dip equator owing to the disturbed northward winds.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315066","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}