Journal of Geophysical Research: Space Physics最新文献

{"title":"Effects of Upstream Drivers on Magnetic Topology at Venus","authors":"Shaosui Xu,&nbsp;Rudy A. Frahm,&nbsp;Yingjuan Ma,&nbsp;Janet G. Luhmann,&nbsp;David L. Mitchell,&nbsp;Moa Persson,&nbsp;Robin Ramstad","doi":"10.1029/2024JA033613","DOIUrl":"https://doi.org/10.1029/2024JA033613","url":null,"abstract":"<p>Although Venus appears to present a predominantly ionospheric obstacle to the solar wind, the magnetic connectivity between the solar wind and the Venus ionosphere, or magnetic topology, is important for characterizing the Venus space environment. In particular, magnetic connectivity is relevant to the magnetization state of the ionosphere, particle precipitation into the atmosphere causing ionization and auroral emissions, and planetary ion escape at Venus. The spatial distributions of different magnetic topologies were statistically analyzed, with some unexpected results. Here, we build on those results by investigating how the external factors of solar cycle phase and upstream conditions affect the occurrence rates of the three magnetic topologies and consider their implications regarding the state of Venus's induced magnetosphere. We find that both the solar cycle phase and upstream dynamic pressure variations control its expansion or contraction. Under solar minimum conditions, the interplanetary magnetic field (IMF) more deeply penetrates into the collisional atmosphere, increasing the occurrence rates of open and closed topologies at low altitudes and in Venus's wake. We also find hemispheric differences in the occurrences of dayside-connected and nightside-connected open fields, likely related to mass loading of the near-Venus plasma environment by planetary pickup ions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of Three-Dimensional Structure and Dynamics of the Large-Scale Sporadic E Layers Over East Asia","authors":"Lihui Qiu,&nbsp;Huixin Liu","doi":"10.1029/2024JA033270","DOIUrl":"https://doi.org/10.1029/2024JA033270","url":null,"abstract":"<p>Sporadic E (Es) layers are thin layers of concentrated metallic ions in the mesosphere and lower thermosphere region. Their occurrence can cause the uneven distribution of plasma density and affects the performance of the Global Navigation Satellite System and high/very high frequency radio communications. Currently, the three-dimensional (3-D) Es layer structure and evolution process have not yet been fully understood. Using the Fe⁺ layer as a proxy for Es layer, in this study, we investigated the structural and dynamic characteristics of the large-scale Es layers extending thousands of kilometers over East Asia by using a 3-D Es layer numerical model driven by neutral winds from the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension model. The simulation results show that the Es layer is a tilted blanket rather than a narrow flat band. In addition, the Es layers mainly occur in the 3-D spatial position of the convergent vertical wind shear. The apparent horizontal velocity (∼300–400 m/s) of Es structure is mostly westward and northward, which is different from the ion drift velocity (∼100 m/s). This indicates that Es structure can develop rapidly over a large area simultaneously rather than only drifting from one location to the next. This study systematically analyzed the physics of the 3-D Es layer, which can be helpful for understanding the Es horizontal structure and dynamics recorded by different instruments, such as satellites and global navigation satellite system receiver networks.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595222","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":"Nonlinear Effects of Ring Current Protons: Impacts of EMIC Wave Amplitude, Frequency, and Propagation Angle","authors":"Su Zhou,&nbsp;Xiaoli Luan,&nbsp;Shangchun Teng,&nbsp;Zhiwei Wang,&nbsp;Shengting Zhu","doi":"10.1029/2024JA033593","DOIUrl":"https://doi.org/10.1029/2024JA033593","url":null,"abstract":"<p>Nonlinear cyclotron resonance is known to cause the scattering of ring current protons to deviate from the predictions of quasi-linear theory, when wave-induced motion dominates over adiabatic motion. This study employed a test-particle simulation to investigate the nonlinear processes of ring current protons and their dependence on the amplitude, frequency, and wave normal angle <i>ψ</i> of electromagnetic ion cyclotron (EMIC) waves. As the equatorial pitch angle α_eq increases, proton motion becomes dominated by the wave's electromagnetic force and responds nonlinearly. When wave-induced motion and adiabatic motion become comparable, the superposition of nonlinear phase trapping and phase bunching leads to complex oscillations in both the test-particle advection and diffusion coefficients. The nonlinear behavior becomes pronounced when the wave amplitude increases significantly. As the wave frequency increases, EMIC waves can nonlinearly interact with lower energy protons (i.e., <i>E</i>_k &lt; 10 keV). Furthermore, oblique EMIC waves tend to produce less significant nonlinear behavior compared to parallel EMIC waves. Increasing the wave normal angle causes the nonlinear regime (i.e., the number of protons responding nonlinearly) in the E_k−α_eq plane to shrink, and the regime changes discontinuously with respect to α_eq. We propose that the characteristics of EMIC waves significantly influence the nonlinear behavior of ring current protons and should be considered in the wave-particle interacting processes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595156","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":"Quasi-Thermal Noise Spectroscopy in Magnetized Space Plasma: Theory and Model","authors":"P. Dazzi,&nbsp;K. Issautier,&nbsp;N. Meyer-Vernet,&nbsp;P. Henri,&nbsp;M. M. Martinović","doi":"10.1029/2024JA033325","DOIUrl":"https://doi.org/10.1029/2024JA033325","url":null,"abstract":"<p>The quasi-thermal noise measured by an electric antenna is routinely used to characterize space plasmas, mainly measuring the electrons' properties. To employ this diagnostic technique, instrumental models are required to turn the instrumental output into physically meaningful measurements. Such models have been developed mainly under the assumption that no magnetic field is present in the plasma. This limit case is not met in planetary magnetospheres, for example, Earth, Mercury. The latter is the objective of the European Space Agency/Japan Aerospace Exploration Agency BepiColombo mission, that has a dedicated quasi-thermal noise experiment. The aim of this work is to extend the current state-of-the-art in quasi-thermal noise modeling by taking into account the magnetic field, therefore providing a plasma diagnostic in this magnetized regime. To achieve this goal, we developed a model for the quasi-thermal noise in a magnetized plasma. We explore four cases: for a Maxwellian and double Maxwellian electron distributions, both in the collisionless limit and in the presence of weak electron-neutral collisions. Our model is validated against known behaviors of the magnetized quasi-thermal noise spectrum, including: the characteristic frequency of maxima and minima, the modulation from the antenna spinning around the magnetic field, the electron temperature(s) influence. We explored parameter ranges that were not accessible to previous quasi-thermal noise models, in particular the high magnetization regime. The model we developed will enable using quasi-thermal noise experiments for the diagnostic of magnetospheric space plasmas, including but not limited to the Hermean and terrestrial magnetospheres, with foreseen applications to future space missions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595157","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":"D-Region Ion-Neutral Collision Frequency Observed by Incoherent Scatter Spectral Width Combined With LIDAR Measurements","authors":"Neethal Thomas,&nbsp;Antti Kero,&nbsp;Ilkka Virtanen,&nbsp;Satonori Nozawa,&nbsp;Norihito Saito","doi":"10.1029/2024JA033587","DOIUrl":"https://doi.org/10.1029/2024JA033587","url":null,"abstract":"<p>We have carried out a statistical study of neutral atmospheric parameters in the mesosphere-lower thermosphere (MLT) region, by utilizing simultaneous measurements from the EISCAT-VHF radar and sodium LIDAR collocated near Tromsø, Norway. This study focuses on the spectral width of the incoherent scatter (IS) signal, which is a function of ion-neutral collision frequency, ion temperature, (equal to neutral temperatures in the D-region), and ion mass. Using the neutral temperatures obtained from LIDAR and ion mass obtained using a chemistry model, we have estimated the ion-neutral collision frequency in 80–100 km altitudes by fitting a theoretical IS spectrum to the EISCAT-VHF measurements. These fitted ion-neutral collision frequencies are then compared with the standard model values obtained using MSIS neutral densities. The study shows that the current widely used model underestimates the ion-neutral collision frequency on average by <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>1.54</mn>\u0000 <mo>±</mo>\u0000 <mn>0.24</mn>\u0000 </mrow>\u0000 <annotation> $1.54pm 0.24$</annotation>\u0000 </semantics></math>. Also, the fitted ion-neutral collision frequencies showed large temporal variations due to neutral density fluctuations, which are absent in the MSIS model. The study demonstrates that these random neutral density fluctuations caused by atmospheric waves can heavily influence the IS spectral width measurements and, therefore, can have a significant impact on ISR analysis when fitting neutral temperatures. The study also demonstrates the presence of heavy cluster ions below 85 km. Large uncertainties in the ion mass make it further challenging to extract the neutral temperature from spectral width below 85 km. In light of these observations, the inherent limitations of inferring temperatures from IS spectral width in the MLT altitudes are discussed.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581726","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":"Stormtime Evolution of the \u0000 \u0000 \u0000 \u0000 O\u0000 +\u0000 \u0000 \u0000 ${mathrm{O}}^{+}$\u0000 Density: Magnetoseismic Analysis of Van Allen Probes Data","authors":"Kazue Takahashi,&nbsp;Richard E. Denton,&nbsp;Peter Chi","doi":"10.1029/2024JA033657","DOIUrl":"https://doi.org/10.1029/2024JA033657","url":null,"abstract":"&lt;p&gt;Measurements of singly ionized oxygen (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) ions in the inner magnetosphere during geomagnetic storms are important because the ions affect various magnetospheric processes. We apply a magnetoseismic technique to Van Allen Probes data to statistically determine the spatial and temporal development of the region of elevated &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; number density &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;n&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({n}_{{mathrm{O}}^{+}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, referred to as the oxygen torus, during geomagnetic storms. This study is motivated by previous studies that reported magnetic local time (MLT) localization of the torus to the morning side. In our study, we first determine the frequencies of the fundamental through third harmonics of toroidal standing Alfvén waves to estimate the mass density &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;mi&gt;ρ&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(rho )$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and then use the electron density &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;n&lt;/mi&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({n}_{mathrm{e}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; derived from plasma wave spectra to define the average ion mass &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;M&lt;/mi&gt;\u0000 &lt;mi&gt;i&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${M}_{mathrm{i}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; (=&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 ","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033657","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571413","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 Density of the Earth's Cusp Region: Three-Dimensional Distribution, Formation, and Influencing Factors","authors":"Tieyan Wang,&nbsp;Chao Xiao,&nbsp;Wenhao Chen,&nbsp;Xiaoxiao Qin,&nbsp;Xiangcheng Dong,&nbsp;Ganming Ren,&nbsp;Hongtao Huang,&nbsp;Die Duan,&nbsp;Yin Xu","doi":"10.1029/2024JA033413","DOIUrl":"https://doi.org/10.1029/2024JA033413","url":null,"abstract":"<p>The Earth's magnetospheric cusp region is an important pathway for solar wind particles entering the magnetosphere and ionospheric ions escaping. The plasma density is a key parameter for understanding this physical process. Based on measurements from the Cluster-3 spacecraft (2001–2010), we selected 878 cusp crossing events (470 in the northern and 408 in the southern hemisphere) and statistically studied the three-dimensional distribution of cusp ion density, its causes, and influencing factors. Our analysis revealed that cusp density is highest at MLT = 12 and decreases as MLT moves away from 12 in both hemispheres; in Solar Magnetic coordinates, the maximum density occurs near the equatorward boundary in the <i>X</i> direction, while in the <i>Z</i> direction, the density shows slight changes. This feature may be largely influenced by the inhomogeneity of magnetic pressure. Furthermore, we found that as the dominant source, solar wind ions enter the cusp effectively near noon and diffuses toward dawn and dusk; the polar ionosphere source becomes important with increasing AE index, transporting particles from a wide MLT range to the cusp; and the dipole tilt angle significantly affects cusp density.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571414","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":"Ionospheric Response to the 10 May 2024 Geomagnetic Storm as Observed in GNSS Radio Occultation Electron Density","authors":"Wonseok Lee,&nbsp;Guiping Liu,&nbsp;Dong L. Wu,&nbsp;Douglas E. Rowland","doi":"10.1029/2024JA033489","DOIUrl":"https://doi.org/10.1029/2024JA033489","url":null,"abstract":"<p>We investigate the spatiotemporal and altitude variations in ionospheric F-region electron density in response to the 10 May 2024 superstorm, the most significant geomagnetic disturbance in two decades. The unprecedented sampling by ∼12,000 electron density profiles each day from the COSMIC-2, Spire and FengYun-3 radio occultation observations provided a nearly global and full local time coverage of this event. During the main phase of the storm, F-region (200–500 km in altitude) electron density decreased globally, with peak electron density height increasing during daytime and decreasing at nighttime in low latitude. Concurrently, topside electron density increased in the low-latitude during the daytime. Additionally, the broadening of the equatorial ionospheric anomaly (EIA) width provides strong evidence of the storm-induced electric field's effect during the storm main phase. Subsequently, the EIA crests merged and remained for about 21 hr during the end of main phase and the recovery phase, suggesting a possible storm-induced equatorial wind impact on the ionosphere. Furthermore, electron density maps reveal hemispheric asymmetry in the storm response. Electron density decreases more effectively in the northern hemisphere than in the southern hemisphere, indicating a significant role of seasonal global circulation during the geomagnetic storm.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565154","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":"Controlling Factors of the Local Time Extent of Magnetopause Reconnection: A Statistical Study","authors":"Krishna Khanal,&nbsp;Ying Zou,&nbsp;Xueling Shi,&nbsp;Gary Zank,&nbsp;J. Michael Ruohoniemi,&nbsp;Kathryn McWilliams","doi":"10.1029/2024JA033392","DOIUrl":"https://doi.org/10.1029/2024JA033392","url":null,"abstract":"<p>Magnetopause reconnection is the dominant mechanism for transporting solar wind energy and momentum into the magnetosphere-ionosphere system. Magnetopause reconnection can occur along X-lines of variable extent in the direction perpendicular to the reconnection plane. Identifying the spatial extent of X-lines using satellite observations has critical limitations. However, we can infer the azimuthal extent of the X-lines by probing the ionospheric signature of reconnection, the antisunward flow channels across the ionospheric Open-Closed Field Line Boundary (OCB). We study 39 dayside magnetopause reconnection events using conjugate in situ and ionospheric observations to investigate the variability and controlling factors of the spatial extent of reconnection. We use spacecraft data from Time History of Events and Macroscale Interactions during Substorms (THEMIS) to identify in situ reconnection events. The width of the antisunward flow channels across the OCB is measured using the concurrent measurements from Super Dual Auroral Radar Network (SuperDARN). Also, the X-line lengths are estimated by tracing the magnetic field lines from the ionospheric flow boundaries to the magnetopause. The solar wind driving conditions upstream of the bow shock are studied using solar wind monitors located at the L1 point. Results show that the magnetopause reconnection X-lines can extend from a few Earth Radii (RE) to at least <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>22 RE in the GSM-Y direction. Furthermore, the magnetopause reconnection tends to be spatially limited during high solar wind speed conditions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033392","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565235","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":"Spatial Dependence of Ion-Kinetic Instabilities in the Earth's Magnetosheath: MMS Observations","authors":"Wence Jiang,&nbsp;Hui Li,&nbsp;Zhongwei Yang,&nbsp;Daniel Verscharen,&nbsp;Chi Wang","doi":"10.1029/2024JA033463","DOIUrl":"https://doi.org/10.1029/2024JA033463","url":null,"abstract":"<p>The Earth's magnetosheath plasma frequently exhibits unequal temperatures parallel and perpendicular to the background magnetic field. This temperature anisotropy is crucial in exciting and dissipating electromagnetic fluctuations in various plasma environments. Leveraging a comprehensive dataset comprising sub-ion scale measurements from NASA's Magnetospheric Multiscale Mission, our study unveils insights into the spatial evolution and parametric dependence of different ion kinetic instabilities within the Earth's magnetosheath. We observe a remarkable spatial dependence on the occurrence of kinetic instabilities. The condition for the mirror-mode instability exhibits a significantly higher prevalence near the subsolar magnetopause compared to the flank regions. The condition for the oblique firehose instability is more prominent near the bow shock region than in the vicinity of the magnetopause. Furthermore, the occurrence of these instabilities and their spatial distribution are linked to the plasma's upstream conditions. Our study offers new insights into the nature of ion kinetic instabilities in the Earth's magnetosheath and similar plasma environments.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565185","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}