Journal of Geophysical Research: Space Physics最新文献

{"title":"Do Solar Eclipses Generate Propagating Ionospheric Perturbations?","authors":"Andrew K. Sun,&nbsp;Hyosub Kil,&nbsp;Hyeyeon Chang,&nbsp;Woo Kyoung Lee,&nbsp;Jiyun Lee","doi":"10.1029/2025JA033746","DOIUrl":"https://doi.org/10.1029/2025JA033746","url":null,"abstract":"<p>Plasma depletion during a solar eclipse is well-documented, but the generation of other forms of ionospheric perturbations by the impact of eclipses is controversial. This study aims to evaluate the generation of additional ionospheric perturbations through case studies of total solar eclipses observed across the United States on 21 August 2017 and 8 May 2024. Total electron content (TEC) values are used to track ionospheric perturbations along the eclipse paths. When a smoothing filter (Savitzky–Golay filter) is applied to detect ionospheric perturbations, negative TEC perturbations are observed during totality, while positive TEC perturbations are detected around the beginning and end of the eclipses. These perturbations, caused by rapid TEC variations during these periods, are interpreted as filtering artifacts. Quasi-periodic multiple TEC perturbation layers are detected along the eclipse paths when an oscillatory filter (polynomial detrending) is applied. However, as this filter introduces wave-like artifacts during detrending, the resulting patterns do not represent actual TEC perturbations. Based on our observational and test results, we conclude that eclipse-induced ionospheric perturbations beyond the well-documented plasma depletion are not evident because actual eclipse-induced perturbations are not distinguishable from filtering artifacts.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033746","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206935","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":"Inferential Evidence for Surprathermal Electron Burst Intensification Due To Inverted-V Precipitation via Inertial Alfvén Waves","authors":"C. Feltman,&nbsp;G. G. Howes,&nbsp;S. R. Bounds,&nbsp;D. M. Miles,&nbsp;C. A. Kletzing,&nbsp;K. Greene,&nbsp;R. Broadfoot,&nbsp;J. Bonnell,&nbsp;R. Roglans","doi":"10.1029/2025JA033869","DOIUrl":"https://doi.org/10.1029/2025JA033869","url":null,"abstract":"<p>The auroral current and electrodynamic structures II sounding rocket mission launched two payloads from Andøya Rocket Range into a post-dusk discrete auroral arc and observed field-aligned electron dispersions near inverted-V precipitation. Five repetitive suprathermal electron bursts (STEBs) associated with low frequency (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>8 Hz) magnetic perturbations are observed on the High Flyer at 400 km altitude. Similar fluctuations on the nearby Low Flyer at 180 km are shown to be Earth-ward traveling Alfvén waves, suggesting the High Flyer also observed Alfvénic activity. The electron bursts occur both coincident and outside inverted-V electrons, with those coincident displaying the highest peak energy and average differential flux values. We interpret the events as wave-particle acceleration via inertial Alfvén waves along near-Earth field lines and employ time-of-flight methods to gauge source altitudes. A Levenberg–Marquardt fitting routine is applied to inverted-V structures near the dispersions to characterize the expected STEB source distributions. We show the differences in STEB behavior are better explained by changes in the resonant source population and not from significant variation in Alfvén wave parameters.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033869","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206775","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":"Variation of Model-Predicted Reconnection Voltages Applied to Uranus' Dayside Magnetosphere","authors":"S. Zomerdijk-Russell,&nbsp;J. M. Jasinski,&nbsp;A. Masters","doi":"10.1029/2025JA033834","DOIUrl":"https://doi.org/10.1029/2025JA033834","url":null,"abstract":"<p>Uranus provides a key missing piece for fundamentally understanding solar wind-magnetospheric interactions due to its location in the outer solar system. Whether the viscous-like interaction overtakes global magnetic reconnection as the dominant process at the magnetopause of the outer planets remains unresolved. Here, we present theoretical predictions of dayside reconnection voltages applied to the Uranian system under different magnetospheric configurations to assess the effectiveness of global magnetic reconnection in the driving of Uranus' magnetosphere. We find the median model-predicted dayside reconnection voltage applied to Uranus' magnetosphere is 22.4 kV. Over just one full planetary rotation, the reconnection voltages are found to vary by tens of kV under Uranus' magnetospheric configuration during its solstice and equinox seasons with fixed solar wind conditions. However, we do not find a significant difference between average voltages at the different seasons, despite the large differences in magnetospheric configuration between solstice and equinox at Uranus. An increase from ∼17 to ∼31 kV in the modeled reconnection voltages is observed when the strength of the interplanetary magnetic field is increased corresponding to expected conditions during solar maximum. Our results suggest that variability resulting from the planet's diurnal rotation and changing solar wind conditions, are more important in controlling the reconnection voltages than seasonal dependencies.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033834","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206915","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":"Anomalous Substorm Signatures During Sudden Solar-Wind Pressure Enhancements","authors":"Shipra Sinha,&nbsp;David G. Sibeck,&nbsp;Mei-ching Fok,&nbsp;Denny Oliveira,&nbsp;A. K. Sinha","doi":"10.1029/2025JA033758","DOIUrl":"https://doi.org/10.1029/2025JA033758","url":null,"abstract":"<p>Magnetospheric substorms, characterized by the rapid release of energy stored in the magnetotail, play a central role in space weather dynamics. These events are typically triggered by enhanced magnetic reconnection between the Earth's magnetic field and the interplanetary magnetic field (IMF). While substorms are often associated with southward IMF orientations, studies have also shown that they can occur even during northward IMF conditions, particularly when solar wind pressure pulses or strong IMF By components are present. This paper examines two unique substorm events, occurring on 06 September 2017 and 19 December 2015, where both events involved minimal IMF Bz and prolonged negative By, alongside coincident pressure pulses. Despite these similar interplanetary conditions, the ground-based magnetic field observations revealed distinct differences in the location and intensity of the auroral electrojet. On 06 September, the electrojet was strongest in the post-midnight sector, whereas on 19 December, the maximum intensity occurred in the dawn sector. Simulations using the OpenGGCM magnetohydrodynamic model reveal that the substorm onset mechanisms differed between the two events. The 06 September event followed a typical IMF By-induced pattern with a shift in onset location to post-midnight, while the 19 December event exhibited an unusual onset, with plasma splitting and propagating sunward in both pre- and post-midnight sectors. These findings suggest that pressure pulses, rather than IMF By, are responsible for large shifts in substorm onset location. The study highlights the need for further investigation into multiple reconnection sites and the role of solar wind pressure in shaping substorm evolution.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033758","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206494","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":"Ionospheric Vertical Correlation Analysis and Modeling Using COSMIC-2 Global Ionospheric Specification Data","authors":"Shuo Liu,&nbsp;Tao Yu,&nbsp;Xiangxiang Yan,&nbsp;Yan Yu,&nbsp;Yu Liang,&nbsp;Kezhi Huang,&nbsp;Yifan Qi","doi":"10.1029/2025JA034008","DOIUrl":"https://doi.org/10.1029/2025JA034008","url":null,"abstract":"<p>The background error covariance matrix is essential in ionospheric data assimilation, enabling the integration of observational data with model predictions by defining spatial relationships between grid points. The vertical component plays a key role in enhancing model accuracy by capturing altitude-dependent spatial correlations, directly influencing electron density profile reconstruction. In this study, we used Constellation Observing System for Meteorology, Ionosphere, and Climate-2 Global Ionospheric Specification data to analyze vertical correlation distances in the ionosphere, identifying the altitude range where the correlation coefficient exceeds 0.75 in both upward and downward directions. The results revealed a clear pattern: vertical correlation distances initially increased with altitude, then the rate of increase slowed or decreased before rising again. Significant variations were observed with local time (LT), geomagnetic latitude, and seasonal effects. Winter anomalies, possibly due to changes in the O/N₂ ratio, amplified vertical correlations, particularly between LT 12:00 and 18:00. A layered Gaussian model was developed to parameterize the vertical correlation coefficients, and its accuracy and adaptability were validated across different seasonal conditions. The model's correlation with observational data was greater than 0.75 across all seasons, with relatively small errors at lower altitudes, typically within 50 km. At reference heights exceeding 500 km, the error range remained within approximately 100 km for most points. These findings contribute to the development of more accurate ionospheric models, which are essential for satellite communication, navigation, and space weather forecasting.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197288","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":"Statistical Analysis of Nonlinear Interactions Between Chorus and Electron Cyclotron Harmonic Waves","authors":"Lixian Yang,&nbsp;Si Liu,&nbsp;Zhonglei Gao,&nbsp;Hongming Yang,&nbsp;Xiongjun Shang,&nbsp;Yang Gao,&nbsp;Fuliang Xiao","doi":"10.1029/2025JA034027","DOIUrl":"https://doi.org/10.1029/2025JA034027","url":null,"abstract":"&lt;p&gt;Nonlinear wave-wave interactions are crucial for extending wave frequency ranges and redistributing energy, thereby influencing the magnetospheric dynamics. The interactions between chorus and electron cyclotron harmonic (ECH) waves can generate the ECH sidebands. Statistical analysis of Van Allen Probes data shows that these interactions primarily occur in the region of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;L&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $L$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 5.0&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;–&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $mbox{--}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;6.0 and MLT = 23&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;–&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $mbox{--}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;09 near the equator &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;|&lt;/mo&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;L&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;mo&gt;|&lt;/mo&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;mn&gt;5&lt;/mn&gt;\u0000 &lt;mo&gt;°&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(vert mathrm{M}mathrm{L}mathrm{A}mathrm{T}vert &lt; 5{}^{circ})$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. As the AE index increases, the ECH sidebands occur over a wider region and their intensity grows. Moreover, the root-mean-square (RMS) amplitude of the ECH sideband &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mo&gt;-&lt;/mo&gt;\u0000 &lt;mtext&gt;RMS&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({E}_{mathrm{S}mbox{-}text{RMS}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is roughly in proportion to the square root of the product of that of the chorus &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mo&gt;-&lt;/mo&gt;\u0000 &lt;mtext&gt;RMS&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({E}_{mathrm{C}mbox{-}text{RMS}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and ECH &lt;span&gt;&lt;/span&gt;&lt;math&gt;","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179012","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":"Statistical Observations in Support of Bow Shock Current Closure to Earth's High-Latitude Ionosphere During Non-Zero IMF By","authors":"G. Nordin,&nbsp;M. Hamrin,&nbsp;E. Krämer,&nbsp;P. Dredger,&nbsp;S. Fatemi,&nbsp;R. E. Lopez,&nbsp;S. E. Milan,&nbsp;T. Pitkänen,&nbsp;T. Karlsson,&nbsp;O. Goncharov","doi":"10.1029/2024JA033599","DOIUrl":"https://doi.org/10.1029/2024JA033599","url":null,"abstract":"&lt;p&gt;The bow shock current (BSC) plays an important role in supplying the magnetosphere with solar wind energy, in particular during times of low solar wind magnetosonic Mach numbers. Since the magnetic pile-up in the magnetosheath has to be maintained, the BSC cannot close locally, but must instead connect to magnetospheric current systems. However, the details of this closure remain poorly understood. For east–west interplanetary magnetic field (IMF) it has been hypothesized that the BSC partly closes to the high-latitude ionosphere, as field-aligned currents (FACs) on open field lines, but there is still no statistical evidence of this. In order to investigate this hypothesis, we use 9 years of Defense Meteorological Satellite Program (DMSP) data to construct normalized FAC maps of the northern hemisphere polar cap. We sort them according to different IMF clock angles, IMF magnitudes and magnetosonic Mach numbers. By separating opposite polarity FACs, we show that, on average, a unipolar FAC exists in the dayside polar cap when the IMF &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;B&lt;/mi&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;≠&lt;/mo&gt;\u0000 &lt;mn&gt;0&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${B}_{y}ne 0$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, regardless of the sign of the IMF &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;B&lt;/mi&gt;\u0000 &lt;mi&gt;z&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${B}_{z}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. This current flows out of (into) the ionosphere in the northern hemisphere for IMF &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;B&lt;/mi&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;0&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${B}_{y} &gt; 0$&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;mo&gt;(&lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;mn&gt;0&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(&lt; 0)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and is thus of the correct polarity to connect to the north–south component of the BSC. Moreover, it is strongest when the BSC flows predominantly in the north–south direction. These results constitute the first statistical evidence in support of at least a partial closure of the BSC to the ionosphere during non-zero IMF &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;se","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033599","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179293","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":"Concurrence and Coupling of EMIC and EFH Instabilities in the Hot Electron Plasma","authors":"Zhiqiang Wang,&nbsp;Jiacheng Zhong,&nbsp;Erkang Zhang,&nbsp;Yufei Li","doi":"10.1029/2024JA033702","DOIUrl":"https://doi.org/10.1029/2024JA033702","url":null,"abstract":"&lt;p&gt;Kinetic instabilities play an important role in the dynamics of the magnetospheric system. Generally, electrons are deemed to be unrelated to the generation of electromagnetic ion cyclotron (EMIC) waves. In this work, a parameter study is performed on the EMIC instability affected by parallel anisotropic electrons (&lt;i&gt;A&lt;/i&gt;&lt;i&gt;&lt;sub&gt;e&lt;/sub&gt;&lt;/i&gt; &lt; 1) in the inner magnetosphere. The wave dispersion relation and wave growth rate are calculated by a numerical method (named PDRK/BO). The plasma instabilities are analyzed and compared by using different combination of parameters (electron temperature, anisotropy and proportion). With the increase of hot electron proportion (&lt;i&gt;N&lt;/i&gt;&lt;i&gt;&lt;sub&gt;e&lt;/sub&gt;&lt;/i&gt;), waves are found to grow successively at &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ω&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $omega &gt; 0.5{{Omega }}_{H}$&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;mi&gt;ω&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $omega &gt; {{Omega }}_{H}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. The minimum electron energies for cyclotron resonance with EMIC waves indicate that the unusual hydrogen band waves at &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ω&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $omega &gt; 0.5{{Omega }}_{H}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; are relevant to the electron resonance mechanism. This is different from the normal hydrogen band waves at &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ω&lt;/mi&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $omega &lt; 0.5{{Omega }}_{H}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, which are the ion resonance mode in nature. The electron firehose (EFH) modes are excited by the parallel anisotropic electrons. Due to the wave couplings between EMIC and EFH modes, the dispersion relations of EMIC waves are changed significantly, and the frequencies at peak growth rates of EMIC waves are moved regularly with the increase of &lt;i&gt;N&lt;/i&gt;&lt;i&gt;&lt;sub&gt;e&lt;/sub&gt;&lt;/i&gt;. Our studies suggest that the energy transfer between electrons and ions h","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171919","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 Survey of Whistler-Mode Waves in the Lunar Plasma Environment: Insights From 11 Years of ARTEMIS Observations","authors":"Abhinav Prasad,&nbsp;Wen Li,&nbsp;Qianli Ma,&nbsp;Xiao-Chen Shen,&nbsp;Anton Artemyev,&nbsp;Andrew R. Poppe,&nbsp;Yuki Harada,&nbsp;Murong Qin,&nbsp;Vassilis Angelopoulos,&nbsp;Mei-Yun Lin","doi":"10.1029/2025JA033820","DOIUrl":"https://doi.org/10.1029/2025JA033820","url":null,"abstract":"<p>Whistler-mode waves are among the most ubiquitously observed plasma waves in the vicinity of Earth's Moon, providing an important diagnostic tool for plasma processes. However, a complete understanding of key plasma parameters responsible for whistler-mode generation remains elusive. In this study, we conduct a comprehensive statistical survey using 11 years of in-situ measurements from the ARTEMIS mission to reveal the global distribution of whistler-mode wave amplitude and occurrence rate as the Moon traverses through the solar wind, magnetosheath, and magnetotail during a typical lunar orbit. Our findings reveal that the highest whistler-mode wave amplitudes are observed when the Moon crosses Earth's magnetosheath. A parametric study is conducted to explore the correlation between whistler-mode wave occurrence rate and plasma parameters such as electron temperature anisotropy and heat flux. These parameters are analyzed separately for low-energy (&lt;100 eV) and high-energy (&gt;100 eV) electrons. The results indicate that whistler-mode wave occurrence rates exhibit a stronger positive correlation with the temperature anisotropy of high-energy electrons compared to low-energy electrons. Moreover, the parallel heat flux (normalized by the free streaming heat flux) of high-energy electrons shows a moderate positive correlation with whistler-mode wave amplitude (normalized to the background magnetic field) in both the solar wind and magnetosheath regions. We further investigate the influence of the background magnetic field line connection to the lunar surface on whistler-mode waves. Overall, our analysis demonstrates that the temperature anisotropy of high-energy electrons has a higher positive correlation with magnetic field connection than that of low-energy electrons.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171920","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":"Statistical Study on the Connections Between TEC Periodic Disturbances Associated With MSTIDs and Mid-Latitude Frequency Spread F in Summer Nights Over China","authors":"Ke Li,&nbsp;Donghe Zhang,&nbsp;Yaoyu Tian,&nbsp;Shuji Sun,&nbsp;Hongyu Gao,&nbsp;Yi Zeng,&nbsp;Guanglin Yang,&nbsp;Yongqiang Hao","doi":"10.1029/2025JA033706","DOIUrl":"https://doi.org/10.1029/2025JA033706","url":null,"abstract":"<p>In this study, the connections between medium-scale traveling ionospheric disturbances (MSTIDs) and mid-latitude frequency spread F (FSF) during summer nights in the China sector are statistically investigated using data from over 250 GNSS stations and 12 ionosonde stations from 2014 to 2018. First, both phenomena are observed to commonly occur on the same night during summer, with longer durations of FSF corresponding to higher average MSTIDs activity values. MSTIDs activity tends to precede the FSF occurrence. The statistical peak distribution of MSTIDs activity is concentrated before midnight, whereas FSF peaks after midnight, with median occurrence time differing by approximately 1–2 hr. Additionally, FSF and MSTIDs exhibit similar spatial propagation characteristics, with occurrences in the northeastern region occurring earlier in universal time (UT). Building on these findings, the potential physical processes and mechanisms by which MSTIDs may excite FSF are further discussed, including the role of E-F coupling, as well as significant changes in critical frequency and virtual height at different MSTIDs activity conditions. Furthermore, the underlying reasons for the differences in the temporal distribution of FSF at different latitudes are also analyzed. The midnight type FSF may be related to the disturbed electric fields in MSTIDs and gradient drift instability, while presunrise type FSF mainly concentrates at higher latitudes, without obvious connections to MSTID activity, suggesting the existence of excitation mechanisms beyond MSTIDs.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179066","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}