Journal of Geophysical Research: Space Physics最新文献

{"title":"Occurrence Rates and Variability of Whistler-Mode Waves in the Plasma Trough","authors":"C. E. J. Watt,&nbsp;N. P. Meredith,&nbsp;J. Wong,&nbsp;K. R. Murphy,&nbsp;I. J. Rae,&nbsp;S. Chakraborty,&nbsp;S. N. Bentley,&nbsp;O. Allanson,&nbsp;C. J. Rodger","doi":"10.1029/2025JA034061","DOIUrl":"https://doi.org/10.1029/2025JA034061","url":null,"abstract":"<p>Numerical models of energetic electron behavior in the outer radiation belt require descriptions of the wave-particle interactions across the inner magnetosphere. Quasilinear diffusion coefficients describe gyro-resonant wave-particle interactions over large time- and length-scales but these must be constrained by observations to construct realistic radiation belt models. Recent work indicates the importance of identifying and including realistic spatiotemporal variation of diffusion coefficients. In this paper, we study the spatiotemporal variability of whistler-mode waves outside the plasmasphere, typically referred to as whistler-mode chorus. We separately consider the probability of (a) parts of the model domain being outside the plasmasphere, and (b) the probability of detecting wave activity should that part of the model domain be outside the plasmasphere. We discover that the spatiotemporal variability of whistler-mode waves significantly differs across the model domain; we propose that wave power variability in short wave intervals (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>5</mn>\u0000 </mrow>\u0000 <annotation> ${sim} 5$</annotation>\u0000 </semantics></math> min) is a useful characteristic to distinguish between two types of whistler-mode waves, especially where their frequency ranges overlap. Our novel spatiotemporal variability analysis indicates that low variability waves are dayside exohiss whose typically high occurrence rate (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>0.8</mn>\u0000 </mrow>\u0000 <annotation> ${sim} 0.8$</annotation>\u0000 </semantics></math>) decreases with substorm activity, and high variability waves are sporadic post-midnight/dawn sector substorm-driven chorus with a typical occurrence rate of 0.2. Further, although previous studies often combine the occurrence rates and wave characteristics into climatological averages of chorus wave power, this study highlights the importance of separating the study of occurrence rates and power of the waves, since each can have a different relationship with driving factors.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224324","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":"A Specification Model of Saturn's Plasma Environment","authors":"A. Kamran,&nbsp;Q. Nénon,&nbsp;F. L. Johansson,&nbsp;Y. Hao,&nbsp;A. Sicard,&nbsp;E. Roussos,&nbsp;K. Dialynas,&nbsp;P. Jiggens,&nbsp;F. Cipriani","doi":"10.1029/2025JA034005","DOIUrl":"https://doi.org/10.1029/2025JA034005","url":null,"abstract":"<p>We present the first empirical-based specification model of Saturn's plasma environment based on the analysis of all publicly available plasma moment data sets derived using multiple techniques from Cassini observations made by the Cassini Plasma Spectrometer and the Radio and Plasma Wave Science instrument. We investigate the variability of the plasma moments with respect to minimum normal distance to the current sheet, L-shell, magnetic latitude, and magnetic local time, and find the latter three parameters to be the most useful to construct the long-term average configuration of plasma moments in Saturn's magnetosphere. The model moments generated by the model include electron and ion densities, temperatures and ion velocities. Given that the majority of the analyzed plasma data are constrained to the equatorial region of Saturn's magnetosphere, we also present an example of extending the plasma model to larger latitudinal ranges with a physics-based extrapolation related to plasma equilibrium. This model will be used to support future space mission planning and development for the Saturnian system, as the moon Enceladus, a planetary body that meets the major criteria for habitability, has been highlighted as a top target for large-scale space missions by various space agencies.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224056","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":"Emission of Energetic Neutral Atoms From Ganymede's Magnetosphere-Atmosphere Interaction","authors":"C. Michael Haynes,&nbsp;Sven Simon,&nbsp;Lucas Liuzzo","doi":"10.1029/2025JA034469","DOIUrl":"https://doi.org/10.1029/2025JA034469","url":null,"abstract":"<p>This study analyzes the emission of energetic neutral atoms (ENAs), generated by charge exchange between energetic protons and Ganymede's atmosphere. We also constrain the observability of such ENAs by an imaging instrument aboard a spacecraft. Our approach employs tracing tools that calculate the trajectories of magnetospheric parent protons near Ganymede. We determine the ENA flux through a hypothetical spherical detector encompassing the moon's atmosphere. We additionally generate synthetic ENA images, as seen by a point-like detector with a finite field of view. The complexity of Ganymede's electromagnetic environment is successively increased; we consider (i) uniform Jovian fields, (ii) the superposition of the moon's internal dipole with Jupiter's field, and (iii) draped fields from a hybrid model of Ganymede's plasma interaction. Our major results are: (a) In uniform fields, the ENA flux is elevated within a circular band on the detector sphere. Synthetic ENA images record a cluster of high flux near the moon's limb, with the position of this enhancement determined by the viewing geometry. (b) When including Ganymede's internal dipole, the flux through the sphere displays a localized increase above the ramside apex, mainly generated by protons on open field lines at mid-latitudes. In the synthetic images, the reduced ENA emissions from the closed field line region produce local flux depletions along the equator. (c) Pile-up of Jupiter's field significantly reduces the ENA flux from Ganymede's ramside atmosphere. (d) At energies above several keV, the emissions from Ganymede's atmosphere clearly exceed the ENA flux released from the moon's surface.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034469","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224067","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":"Latitudinal Profiles of Nightside Isotropy Boundaries: Comparison of Observations and Predictions of Adaptive Magnetospheric Model","authors":"V. A. Sergeev,&nbsp;M. V. Kubyshkina,&nbsp;I. V. Kubyshkin,&nbsp;A. Artemyev,&nbsp;V. Angelopoulos","doi":"10.1029/2025JA034428","DOIUrl":"https://doi.org/10.1029/2025JA034428","url":null,"abstract":"<p>There is significant interest in monitoring the instantaneous magnetic configurations and dynamic states of the magnetotail and understanding what controls them. A unique and attractive opportunity is provided by remote sensing of the radial profile of the equatorial magnetic field curvature based on low-latitude energetic particle measurements of isotropy boundaries (IBs), providing that you can determine the origin of isotropic precipitation. To validate the magnetic field line curvature scattering (FLCS) as the main mechanism of the isotropy boundary formation, we compare coarse energy versus latitude IB profiles (in 3 + 3 energy channels) measured during a few dozen passes of POES and ELFIN spacecraft with the theoretical predictions of the adapted (AM03) magnetospheric model. Two studied intervals in August 2022 include substorm events of various intensities for which good spacecraft coverage in the near magnetotail helps reconstruct the adaptive model in the areas where the IBs are formed. We find a general agreement between the predicted and observed <i>coarse</i> IB profiles' shape and latitude, validating the FLCS hypothesis. Deviations are also observed, and we discuss the factors that can influence identification of the true FLCS profiles in observations and predictions, including limitations of adaptive modeling, non-monotonic radial structure of the tail magnetic field, and interference of FLCS with other precipitation mechanisms related to wave-particle interactions. Most can be avoided by improving the sensitivity, energy coverage, and resolution in future instruments.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224065","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":"Wisp-Like Energy Spectrum of Precipitating Electrons Observed by DEMETER Satellite","authors":"Jingle Hu,&nbsp;Binbin Ni,&nbsp;Yangxizi Liu,&nbsp;Junhu Dong,&nbsp;Jianhang Wang,&nbsp;Haozhi Guo,&nbsp;Jiakun Dai,&nbsp;Zheng Xiang","doi":"10.1029/2025JA034457","DOIUrl":"https://doi.org/10.1029/2025JA034457","url":null,"abstract":"<p>Very-low-frequency (VLF) signals used for submarine communication can penetrate the ionosphere and leak into the magnetosphere. These signals interact with hundreds of keV electrons in the inner magnetosphere through cyclotron resonance, resulting in pitch angle diffusion of trapped electrons. The energy-<i>L</i> spectrum of quasi-trapped electrons (in the drift loss cone scattered by North West Cape (NWC) transmitted signals in the inner radiation belt is called “wisp,” characterized by narrow spectral peaks of enhanced fluxes. These quasi-trapped electrons drift eastward and can be clearly observed by Low-Earth-Orbit satellites until they precipitate into the South Atlantic Anomaly (SAA) region, where they drift into the bounce loss cone (BLC). The transmitter-induced BLC precipitation with a wisp structure has been considered uncommon. In this study, we report the direct and clear observational evidence of transmitter-induced precipitating wisps which are commonly observed at the edge of the northern hemisphere precipitation regions (the regions conjugated to the SAA). Moreover, we systematically analyze the dependence of these electron fluxes on <i>L</i>-shell, electron energies and geomagnetic activities, using long-term measurements from the DEMETER satellite. The intensities and positions of the precipitating wisps in the energy-<i>L</i> spectrum are highly correlated with the quasi-trapped wisps. The visible wisp structure in the precipitating electrons can only be detected when the quasi-trapped electron fluxes exceed a certain threshold ∼10³ cm⁻²ster⁻¹s⁻¹ MeV⁻¹. The overall variation in precipitating electron fluxes follows the trend observed in trapped electron fluxes. These results provide new insights into the quantitative scattering effects of NWC transmitter signals on energetic electrons.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223783","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":"Electrostatic Charging of Lunar Cavities Governed by the Flow-to-Thermal Speed Ratio: 3D PIC Simulations and a Free-Fall Model","authors":"J. Nakazono,&nbsp;Y. Miyake,&nbsp;W. J. Miloch","doi":"10.1029/2025JA034302","DOIUrl":"https://doi.org/10.1029/2025JA034302","url":null,"abstract":"&lt;p&gt;We use Particle-In-Cell (PIC) simulations to investigate the charging characteristics inside deep cavities on the lunar surface under the solar wind plasma conditions. Specifically, we systematically study the dependence of the cavity bottom potential on plasma flow velocity and cavity aspect ratio. In light of prior results indicating that the charging characteristics are predominantly determined by the cavity aspect ratio, the present analysis employs a rectangular shape for the cavity with a width smaller than the local Debye length. Three flow regimes are then defined according to the ordering among the bulk flow velocity (&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;mi&gt;flow&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{mathrm{flow}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and the ion thermal velocity (&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;mtext&gt;ti&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{text{ti}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and the electron thermal velocity (&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;mtext&gt;te&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{text{te}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;); low (&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;mtext&gt;flow&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mtext&gt;ti&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{text{flow}}&lt; {v}_{text{ti}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;), medium (&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;mtext&gt;ti&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mtext&gt;flow&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mtext&gt;te&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${v}_{text{ti}}&lt; {v}_{text{flow}}&lt; {v}_{text{te}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;), and high (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 ","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034302","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224055","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":"A Global Map of Average Electron Densities in the Magnetosphere of Saturn","authors":"Ulrich Taubenschuss,&nbsp;Ondřej Santolík,&nbsp;David Píša,&nbsp;Masafumi Imai,&nbsp;Georg Fischer,&nbsp;Siyuan Wu,&nbsp;Michiko W. Morooka,&nbsp;William S. Kurth","doi":"10.1029/2025JA034007","DOIUrl":"https://doi.org/10.1029/2025JA034007","url":null,"abstract":"<p>Measurements from the Cassini Radio and Plasma Wave Science (RPWS) experiment obtained during the entire orbital phase of the Cassini mission around Saturn (13.2 years) are processed into a meridional map of plasma densities, comprising the innermost region of the ring ionosphere, the Enceladus plasma torus, and the outer magnetosphere, up to a dipole L-shell of 30. We combine data from RPWS wave observations, such as whistler-mode waves and upper hybrid electrostatic emissions, and from the RPWS Langmuir probe when operated in the proxy mode, providing an estimate for the spacecraft potential. In the region between dipole L-shells of 2.4 and 30, observed electron densities are described by an analytic model that fits two functions, one for the water group ions and one for the protons, to observed densities across latitude on each magnetic field line. The derived electron density profiles are then augmented by a model for the cold core electron temperature as a function of L-shell to obtain a meridional map of the electrostatic potential of the ambipolar electric field. The potential is extrapolated to the inner region of the rings, i.e., to below <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>=</mo>\u0000 <mn>2.4</mn>\u0000 </mrow>\u0000 <annotation> $L=2.4$</annotation>\u0000 </semantics></math>, to solve for the distribution of electron density in the ring ionosphere. A solution is based on a diffusive equilibrium model for the electrons and two ion species, and on observations from Cassini along the Saturn Orbit Insertion trajectory. A combination of analytic and diffusive equilibrium results finally yields an average global picture for the distribution of electron density in Saturn's magnetosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224066","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":"The Role of Pedersen Conductance on the Dawn-Dusk Asymmetries in Jupiter's Magnetosphere-Ionosphere System: Model-Data Comparisons","authors":"A. R. Smith,&nbsp;P. A. Delamere,&nbsp;C. E. Spitler,&nbsp;D. S. Ozturk,&nbsp;V. A. Palmer,&nbsp;J. Caggiano,&nbsp;K. Sorathia,&nbsp;A. Sciola,&nbsp;J. Z. Wang,&nbsp;R. J. Wilson,&nbsp;F. Bagenal","doi":"10.1029/2025JA034189","DOIUrl":"https://doi.org/10.1029/2025JA034189","url":null,"abstract":"<p>Jupiter's rapidly rotating magnetosphere, with internal plasma sources such as the volcanic moon Io, provides a unique natural laboratory for studying internally driven planetary magnetospheres. Using the Grid Agnostic Magnetohydrodynamics for Extended Research Applications (GAMERA) model, we simulated Jupiter's magnetosphere with variable ionospheric Pedersen conductances, which is mainly responsible for energy dissipation between the ionosphere and magnetosphere though convection. We chose values ranging from 0.5 to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>6</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $1{0}^{6}$</annotation>\u0000 </semantics></math> mho <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mo>℧</mo>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation> $(mho )$</annotation>\u0000 </semantics></math> to investigate the Pedersen conductance's role in controlling mid-magnetosphere region's dynamics and the closing of magnetosphere-ionosphere currents. Simulated density, temperature, and radial and azimuthal flows in the equator are compared with observations from the Jovian Auroral Distributions Experiment (JADE) on the Juno spacecraft. All simulation cases exhibit dawn-dusk asymmetries, in both the ionosphere and magnetosphere. The 0.5 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>℧</mo>\u0000 </mrow>\u0000 <annotation> $mho $</annotation>\u0000 </semantics></math> case showed the best agreement with JADE observations, while the 1 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>℧</mo>\u0000 </mrow>\u0000 <annotation> $mho $</annotation>\u0000 </semantics></math> case exhibited a magnetic topology more consistent with the auroral observations from the Hubble Space Telescope and Juno. These results enhance our understanding of Jupiter's magnetosphere-ionosphere coupling, provide context for observations, and inform the background parameters of future test particle simulations and data-model comparisons using the GAMERA model.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224101","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":"Dominant Trends in Jupiter's \u0000 \u0000 \u0000 \u0000 \u0000 H\u0000 3\u0000 +\u0000 \u0000 \u0000 \u0000 ${mathbf{H}}_{mathbf{3}}^{mathbf{+}}$\u0000 Northern Aurora: II. Magnetospheric Mapping","authors":"Tom S. Stallard,&nbsp;Katie L. Knowles,&nbsp;Henrik Melin,&nbsp;Ruoyan Wang,&nbsp;Emma M. Thomas,&nbsp;Luke Moore,&nbsp;James O’Donoghue,&nbsp;Rosie E. Johnson,&nbsp;Steve Miller,&nbsp;John C. Coxon","doi":"10.1029/2025JA034076","DOIUrl":"https://doi.org/10.1029/2025JA034076","url":null,"abstract":"<p>Jupiter's auroral regions have previously been defined by broad-scale auroral structures, but these are typically obscured by the wide array of temporal variability observed at timescales between minutes and days, making it difficult to understand the underlying magnetospheric biases driving these brightness differences. Here, we follow on from an initial study of Jupiter's aurora, again utilizing a data set of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>13,000 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>H</mi>\u0000 <mn>3</mn>\u0000 <mo>+</mo>\u0000 </msubsup>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${mathrm{H}}_{3}^{+}$</annotation>\u0000 </semantics></math> images of Jupiter mapped into latitude, longitude and local time, smoothed over tens of hours of integration and many days of observing. Having removed correlations between brightness and both magnetic field and planetary local time identified in the first study, we examine morphological changes in emission with both planetary and magnetic local time. We reveal that the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>H</mi>\u0000 <mn>3</mn>\u0000 <mo>+</mo>\u0000 </msubsup>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${mathrm{H}}_{3}^{+}$</annotation>\u0000 </semantics></math> main auroral emission is enhanced by a factor of three in the region mapping into the dusk magnetosphere. An additional strong auroral darkening is observed near noon, aligned with previous ultraviolet observations of an auroral discontinuity in this region, though this rotates duskward slightly in magnetic local time, as the ionospheric source mapping to this region moves duskward. The polar aurora contrasts with this strongly, showing brightness enhancement when the auroral pole points toward the dawn and dusk limbs. It also shows that the Dark region is fixed in local time, close to the dawnward edge of the polar region, while the Swirl region appears to match well with predictions from recent MHD models when the magnetic pole points toward dawn, but changes significantly at other magnetic pole directions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224099","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":"Comparative Study of Ion and Electron Average Pressure Variation in the Inner Magnetosphere During CIR- and ICME-Driven Storms Observed by the Arase Satellite","authors":"Sandeep Kumar,&nbsp;Y. Miyoshi,&nbsp;Y. Zheng,&nbsp;V. K. Jordanova,&nbsp;L. M. Kistler,&nbsp;K. Yamamoto,&nbsp;T. Hori,&nbsp;C. Jun,&nbsp;K. Asamura,&nbsp;S. Yokota,&nbsp;S. Kasahara,&nbsp;Y. Kazama,&nbsp;S.-Y. Wang,&nbsp;Sunny W. Y. Tam,&nbsp;T.-F. Chang,&nbsp;B.-J. Wang,&nbsp;T. Mitani,&nbsp;T. Takashima,&nbsp;K. Keika,&nbsp;A. Matsuoka,&nbsp;S. Imajo,&nbsp;I. Shinohara","doi":"10.1029/2025JA034182","DOIUrl":"https://doi.org/10.1029/2025JA034182","url":null,"abstract":"<p>Using Arase satellite observations, this study provides a comprehensive statistical analysis of ions (H⁺, He⁺, O⁺) and electron contributions to the total ring current pressure during storms with two different drivers. The results demonstrate the effect of different solar wind drivers on the composition, energy distribution, and spatial characteristics of the ring current. Using 32 CIR- and 30 Interplanetary Coronal Mass Ejection (ICME)-driven storms, we characterize the ring current pressure evolution during the prestorm, main, early-recovery, and late-recovery storm phases as a function of magnetic local time and <i>L</i>-shell. In CIR-driven storms, H⁺ ions are the dominant (∼70%) contributor to the total ring current pressure during main/early recovery phases and increasing to ∼80% during late recovery. In contrast, the O⁺ pressure (<i>E</i> = 20–50 keV) response is significantly stronger in ICME-driven storms contributing ∼40% to the overall pressure during the main/early recovery phases and even dominate (∼53%) in certain MLT sectors. Additionally, ICME-driven storms tend to have peak pressure at lower <i>L</i>-shells (<i>L</i> ≈ 3–4), while CIR-driven storms show pressure peaks at slightly higher <i>L</i>-shells (<i>L</i> ≈ 4–5). Interestingly, electron pressure also plays a notable role in specific MLT sectors, contributing ∼18% (03–09 MLT) during the main phase of CIR-driven storms and ∼11% (21–03 MLT) during ICME-driven storms. The results highlight that the storm time electron pressure plays a crucial role in the ring current buildup. Another noteworthy feature of this study is that Arase's fine-energy resolution and broad coverage enable a detailed investigation of energy-dependent ring current dynamics.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224100","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}