Journal of Geophysical Research: Space Physics最新文献

{"title":"Parametric Study on the Interplay Between ECH and Whistler Waves: Particle-In-Cell Simulations","authors":"Tong Shao, Xinliang Gao, Yangguang Ke, Jiuqi Ma, Wentian Lei, Quanming Lu","doi":"10.1029/2025JA033980","DOIUrl":"https://doi.org/10.1029/2025JA033980","url":null,"abstract":"<p>Electron Cyclotron Harmonic (ECH) waves and whistler waves are common plasma waves in the Earth's magnetosphere, and they play an important role in regulating electron dynamics. Recent observations reveal that whistler waves can suppress ECH waves by reshaping the electron distribution, but a comprehensive study on the effects of various plasma parameters on their interplay is still lacking. Using a two-dimensional (2-D) particle-in-cell (PIC) simulation model, we have thoroughly studied the evolution of ECH waves under various initial plasma conditions by relaxing anisotropic hot electrons with a loss-cone distribution. Overall, ECH waves are significantly suppressed once whistler waves appear, and their damping rate is strongly dependent on the amplitude of whistler waves, which is positively correlated with the hot electron proportion and the temperature anisotropy. Moreover, the final amplitude ratio <i>R</i> between ECH and whistler waves tends to increase with a higher hot electron proportion <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>n</mi>\u0000 <mi>h</mi>\u0000 </msub>\u0000 <mo>/</mo>\u0000 <msub>\u0000 <mi>n</mi>\u0000 <mi>e</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${n}_{h}/{n}_{e}$</annotation>\u0000 </semantics></math>, lower temperature anisotropy <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>A</mi>\u0000 </mrow>\u0000 <annotation> $A$</annotation>\u0000 </semantics></math>, and higher ratio of plasma frequency to electron cyclotron frequency <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>f</mi>\u0000 <mtext>pe</mtext>\u0000 </msub>\u0000 <mo>/</mo>\u0000 <msub>\u0000 <mi>f</mi>\u0000 <mtext>ce</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${f}_{text{pe}}/{f}_{text{ce}}$</annotation>\u0000 </semantics></math>. However, it shows little dependence on the size of loss-cone width <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 </mrow>\u0000 <annotation> $beta $</annotation>\u0000 </semantics></math> and parallel temperature <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>T</mi>\u0000 <mo>∥</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${T}_{mathit{{Vert} }}$</annotation>\u0000 </semantics></math>. This study not only supports that the suppression of ECH waves by whistler waves is a common phenomenon but also provides some new insights into understanding the global distribution of EC","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695821","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":"Revealing Significant Differences in Horizontal Correlation Distances of E-Layer and F-Layer Based on COSMIC-2 GIS Data","authors":"Shuo Liu,&nbsp;Tao Yu,&nbsp;Xiangxiang Yan,&nbsp;Yifan Qi,&nbsp;Yan Yu,&nbsp;Kezhi Huang,&nbsp;Zukang Dai","doi":"10.1029/2024JA033532","DOIUrl":"https://doi.org/10.1029/2024JA033532","url":null,"abstract":"<p>Building an accurate background covariance matrix is crucial for ionospheric data assimilation. This matrix quantifies the correlations between grid points and governs the transition between data-driven and model-driven regions. Due to the ionosphere's layered structure and the diverse physical mechanisms operating at different altitudes, the correlation distances vary significantly across layers. While previous studies have primarily focused on Total Electron Content data or F-layer peak electron densities, the E-layer has received little attention. To address this gap, we analyzed the Constellation Observing System for Meteorology, Ionosphere, and Climate-2 Global Ionospheric Specification (GIS) (COSMIC-2 GIS) data from 2020 to 2022, conducting the first study on horizontal spatial correlations in the E-layer (120 km). This study also compared the similarities and differences between the horizontal correlations of the E-layer (120 km) and F-layer (300 km). Our analysis examined how correlation distances vary with local time, geomagnetic latitude, and seasons. The results revealed significant differences in spatial coherence between the two layers: the F-layer exhibits a single-peak structure, with zonal correlation distances greater than meridional correlation distances, while the E-layer shows a more complex double-peak structure, with pronounced peaks at sunrise and sunset. Finally, we developed a horizontal correlation coefficient model based on dual-Gaussian functions at different altitudes. These findings enhance our understanding of ionospheric dynamics and support the construction of more accurate background error covariance matrices, ultimately improving ionospheric modeling and space weather forecasting accuracy.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695847","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}

{"title":"Characteristics of Gravity Wave-Excited Disturbances Observed in HFSWR Ocean-Ionosphere System During Typhoons","authors":"Rong Wang,&nbsp;Changjun Yu,&nbsp;Zhe Lyu,&nbsp;Xuguang Yang","doi":"10.1029/2024JA033256","DOIUrl":"https://doi.org/10.1029/2024JA033256","url":null,"abstract":"<p>In this study, the intricate gravity wave-excited disturbances in the ocean-ionosphere system is investigated using the high-frequency surface wave radar (HFSWR) data measured during typhoons. To address the nonstationarity of HFSWR echoes during typhoons, a multilayer denoising preprocessing model based on local mean decomposition is introduced. For qualitative analysis of the disturbance relationship between the ocean and ionosphere at smaller time scales, a fuzzy equivalence coefficient based on HFSWR chaotic attractors is designed, integrating fuzzy set theory. To maximize the presentation of the disturbance characteristics excited by gravity waves, an adaptive optimization method based on the fuzzy equivalence coefficients of HFSWR chaotic attractors is constructed. In summary, an adaptive fuzzy evaluation method based on HFSWR chaotic attractors to characterize the nonlinear evolution process of HFSWR oceanic-ionospheric echoes excited by gravity waves is proposed in this paper. Disturbance features in HFSWR oceanic echoes that exhibit the same evolution trends as traveling ionospheric disturbances (TIDs) excited by gravity waves are successfully identified in this study, thus confirming the presence of gravity wave-excited disturbances in HFSWR ocean-ionosphere system. Experimental studies also demonstrate the validity of the proposed adaptive fuzzy evaluation approach.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144657743","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":"Multi-Fluid MHD Study of the Disappearing Solar Wind Event Observed by MAVEN: Effects of Solar Wind Density","authors":"Yingjuan Ma,&nbsp;Jasper S. Halekas,&nbsp;Shaosui Xu,&nbsp;Christopher M. Fowler,&nbsp;Janet G. Luhmann,&nbsp;Xiaohua Fang,&nbsp;Gabor Toth,&nbsp;Shannon Curry","doi":"10.1029/2025JA033997","DOIUrl":"https://doi.org/10.1029/2025JA033997","url":null,"abstract":"<p>Using the latest Mars Multi-fluid Magneto-hydrodynamic (MHD) model (Y. J. Ma et al., 2019, https://doi.org/10.1029/2019ja027091), we examined an extremely low solar wind density event observed by Mars Atmosphere and Volatile Evolution (MAVEN) on 26 December 2022. Simulation results show that the solar wind density plays a crucial role in plasma interactions. The interaction region expands significantly from less than 2 R_M under typical solar wind density conditions to more than 4 R_M along the subsolar line for extremely low solar wind density (&lt;0.1 cm⁻³), consistent with MAVEN observations during the event. Under low solar wind density conditions, the ion pickup plume becomes smaller and is associated with a lower flow speed. Model results also show a nonlinear correlation between the solar wind density and the ion escape rates. Specifically, when the solar wind density is relatively high (&gt;0.2 cm⁻³), the total ion loss rate positively correlates with the solar wind density. However, when the solar wind density is extremely low, ion escape rates are nearly constant despite further decreases in solar wind density. For this event, the solar wind density dropped by over an order of magnitude, while the MHD model predicts the total ion escape rate reduced by approximately a factor of ∼3. Additionally, we investigated possible reasons for the sudden drop in magnetic field strength during the inbound segment of two consecutive orbits and found that a sudden change of the interplanetary magnetic field direction to radial configuration could also attribute to the observed field decrease.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635597","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":"Coupling Between Earth′s Magnetotail and the Outer Radiation Belt via Field-Line Curvature Scattering","authors":"A. V. Artemyev,&nbsp;V. Angelopoulos,&nbsp;X.-J. Zhang,&nbsp;J. Bortnik,&nbsp;Y. Miyoshi,&nbsp;C. Wilkins,&nbsp;S. Kasahara,&nbsp;T. Hori,&nbsp;A. Matsuoka,&nbsp;T. Mitani,&nbsp;T. Takashima,&nbsp;M. Teramoto,&nbsp;K. Yamamoto,&nbsp;I. Shinohara","doi":"10.1029/2025JA034184","DOIUrl":"https://doi.org/10.1029/2025JA034184","url":null,"abstract":"<p>The Earth's outer radiation belt is populated by relativistic (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≥</mo>\u0000 <mn>500</mn>\u0000 </mrow>\u0000 <annotation> ${ge} 500$</annotation>\u0000 </semantics></math> keV) electrons, which are typically confined by the strong dipole magnetic field but can precipitate into the atmosphere through scattering by electromagnetic waves. In contrast, the magnetotail primarily contains electrons with energies below 200 keV, which are predominantly scattered and precipitated due to magnetic field-line curvature scattering (FLCS). In this study, we demonstrate that FLCS can also scatter and precipitate relativistic electrons from the outer radiation belt. Using coordinated observations from the ERG/Arase satellite and low-altitude ELFIN CubeSats in the outer radiation belt, we compare electron fluxes across different <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 <annotation> $L$</annotation>\u0000 </semantics></math>-shells and energy ranges. Our analysis reveals that the outer edge of the radiation belt exhibits isotropic electron populations above a minimum energy that increases with proximity to Earth. Such isotropization energy dependence on distance, or <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 <annotation> $L$</annotation>\u0000 </semantics></math>-shell, agrees with that observed simultaneously at the ELFIN satellite, at low-Earth orbit, where it has been known as the electron isotropy boundary (IBe). This agreement between low-altitude and near-equatorial observations during satellite conjunctions suggests that the <i>IBe pattern</i> may extend to the outskirts of the traditional outer radiation belt. From that distance, the associated FLCS may facilitate precipitation of relativistic electrons up to several MeV. Therefore, FLCS—known to shape the <i>IBe pattern</i> —plays a key role in radiation belt dynamics.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624608","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":"Magnetic Field Dynamics in MAAX Satellite's Circular Polar Orbit: A Magnetic Model Comparison","authors":"Sanjay Kumar,&nbsp;Mark B. Moldwin","doi":"10.1029/2025JA033975","DOIUrl":"https://doi.org/10.1029/2025JA033975","url":null,"abstract":"<p>Motivated by the unique high-altitude polar orbit of the NASA Magnetosphere Auroral Asymmetry eXplorer (MAAX) mission and its Magnetometer Array Distributed on MAAX (MADMAAX), we examine the high-altitude magnetic field environment and its response to solar wind conditions. Using a data set from the Polar satellite magnetometer, we investigate the variations in the external magnetic field along its highly elliptical orbit. To obtain the external magnetic field, we subtract the internal field, estimated using the IGRF-95 model, from the observed data. Additionally, we compare the Polar observations with four empirical magnetospheric magnetic field models (T89, T96, T01, and T04) along the satellite's orbit. Our comparison of the observed external magnetic field with the modeled fields finds that the T01 model provides the most accurate predictions, even near the satellite's perigee, outperforming the other models (T89, T96, T04) for the data set used. To extend our findings, we simulate an artificial circular polar orbit with a radius of 7 RE, matching the proposed MAAX mission trajectory, and calculate the magnetic field distribution along this orbit using the T01 model. The results demonstrate that the T01 model reliably approximates the magnetic field for such a high-altitude circular polar orbit, highlighting its utility for future mission planning. Our findings provide valuable insights into the dependence of the external magnetic field on solar wind conditions, offering a better understanding of geomagnetic variations in the high-altitude regions and supporting the design and data interpretation of future missions like MAAX.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033975","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624693","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 a Propagation of Gendrin-Mode Waves in the Magnetosphere","authors":"Anatoly V. Streltsov","doi":"10.1029/2025JA034200","DOIUrl":"https://doi.org/10.1029/2025JA034200","url":null,"abstract":"<p>This paper presents results from the analytical and numerical investigations of the propagation of Gendrin-mode whistler waves in the magnetosphere. These waves are important for the interpretation of satellite observations and planning experiments in laboratory and space plasma because the perpendicular component of their group velocity is equal to zero, and hence, they can supposedly propagate over a significant distance along an ambient magnetic field without attenuation. Simulations of the electron MHD equations demonstrate that these waves generated by the source with a finite transverse size experience a substantial diffraction, leading to the diminishing of wave amplitude with distance from the source. The effect of the diffraction is inversely proportional to the transverse size of the wave packet. Simulations also reveal that these waves can be trapped and guided along the ambient magnetic field by the field-aligned irregularities (aka ducts) in the plasma density or the magnetic field. Specifically, the Gendrin-mode waves can be efficiently trapped by the low-density or high-magnetic ducts with a very small (1%) difference in magnitudes of the parameters inside and outside the ducts. High-density and low-magnetic ducts do not trap these waves.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624605","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}