Journal of Geophysical Research: Space Physics最新文献

{"title":"Local Generation of Mirror Modes by Pickup Protons at Mars","authors":"C. Simon Wedlund,&nbsp;C. Mazelle,&nbsp;K. Meziane,&nbsp;C. Bertucci,&nbsp;M. Volwerk,&nbsp;L. Preisser,&nbsp;D. Schmid,&nbsp;J. Halekas,&nbsp;J. McFadden,&nbsp;D. Mitchell,&nbsp;J. Espley,&nbsp;P. Henri","doi":"10.1029/2024JA033275","DOIUrl":"https://doi.org/10.1029/2024JA033275","url":null,"abstract":"<p>Mirror mode structures are born from a plasma instability driven by a large temperature anisotropy and appear downstream of planetary and interplanetary shocks, in their magnetosheath. As so-called “magnetic bottles” imprisoning dense and hot plasma, they are usually observed downstream of their region of formation, where the anisotropy is large and free energy is available, implying that they are advected with the plasma flow to the detection region. At Earth and other planets, the quasi-perpendicular shock provides the plasma with the necessary heating along the perpendicular direction to the local magnetic field. At Mars, which boasts an extended exosphere, an additional source of temperature anisotropy exists, through unstable ring-beam velocity distributions, that is, through ions locally ionized and subsequently picked up by the local electric fields. We report here for the first time an example of near locally-generated mirror mode structures due to pickup protons at Mars using the full plasma instrument suite on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. We present events with mirror modes in quasi-perpendicular and quasi-parallel shock conditions, discuss the locality of their generation and show that, in addition to the classic quasi-perpendicular source of anisotropy, another source exists, that is, unstable pickup protons. The existence at Mars of this extra ion anisotropy-generating mechanism is reminiscent of comets.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119657","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 Numerical Investigation of Equatorial Electrojet During the Total Solar Eclipse on 29 March 2006","authors":"Kedeng Zhang,&nbsp;Hui Wang,&nbsp;Jiuhou Lei,&nbsp;Tong Dang,&nbsp;Huimin Song,&nbsp;Hao Xia","doi":"10.1029/2024JA033041","DOIUrl":"https://doi.org/10.1029/2024JA033041","url":null,"abstract":"<p>Due to the relative location of the Sun, Earth, and Moon, a common and special phenomenon occurs, termed a solar eclipse. During the solar eclipse, the solar radiation is greatly obscured, therefore, a series of disturbances could be imposed into the ionosphere. Using electron density observations from the Challenging Minisatellite Payload satellite, the equatorial electrojet (EEJ) measurements from the ground station, and simulations from the Thermosphere Ionosphere Electrodynamic General Circulation Model, this work explored the behaviors of EEJ during the total solar eclipse on 29 March 2006. The path of this solar eclipse goes across the dip equator, providing an opportunity for us to explore the perturbations of EEJ. It is found that the observed EEJ at the MBO station is reduced, with a maximum and average percentage of 38.85% and 19.43%, respectively. The perturbations of EEJ are not only established that are directly affected by the solar eclipse but also after the solar eclipse ends. Local Cowling conductivity associated with E-region electron density is greatly decreased when the solar eclipse occurs. The zonal electric field established by the E-region wind might play a key role in the regulation of EEJ in both eclipse and post-eclipse phases.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119862","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":"The Role of Local Acceleration and Radial Diffusion in Multi-MeV Electron Flux Enhancements","authors":"A. A. Saikin,&nbsp;A. Y. Drozdov,&nbsp;A. N. Jaynes,&nbsp;D. Kondrashov,&nbsp;A. Boyd,&nbsp;Y. Y. Shprits","doi":"10.1029/2024JA033180","DOIUrl":"https://doi.org/10.1029/2024JA033180","url":null,"abstract":"<p>During the Van Allen Probes era, several multi-MeV (&gt;4 MeV) electron flux enhancements were observed. The cause of electron acceleration up to multi-MeV remains an ongoing science topic. In this study, we focus on examining the relationship between phase space density (PSD) radial profile shapes and the occurrence of multi-MeV electron flux enhancement events. This will determine which process (local acceleration or radial diffusion) is dominant in producing multi-MeV electron flux enhancements at a specific L*. Growing peaks in PSD radial profiles are associated with the local acceleration (i.e., a wave-particle interaction) of multi-MeV electrons. For each growing peak in PSD, we determined the L* where the local acceleration occurs for each respective electron energy. Similarly, we also identify which PSD profiles are related to acceleration via radial diffusion profiles. Both sets of profiles are compared with the Van Allen Probe-A observed multi-MeV electron flux enhancements. Results show that both mechanisms (local acceleration and radial diffusion) can facilitate multi-MeV electron acceleration, however each mechanism has a preferable L* region where it is the dominant acceleration process.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119382","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":"Characterization and Modeling of Equatorial Ionization Anomaly Crest and Trough Positions Using Multiple-Source Fused Data During the Solar Minimum Period","authors":"Kaixin Wang,&nbsp;Jiandi Feng,&nbsp;Ting Zhang,&nbsp;Zhenzhen Zhao,&nbsp;Baomin Han","doi":"10.1029/2024JA033558","DOIUrl":"https://doi.org/10.1029/2024JA033558","url":null,"abstract":"<p>Characterizing the spatial and temporal variations of the equatorial ionization anomaly (EIA) is essential for understanding ionospheric dynamical processes and further developing empirical total electron content (TEC) models. Using the multiple-source fused TEC data during the solar minimum period, the EIA crest and trough positions were extracted, analyzed, and modeled. We primarily investigated the longitudinal differences in the probability of bimodal occurrence (PBO) and its time dependence at each longitude. The main results are as follows: (a) The PBO exhibits significant longitudinal variation, with a wave-number-3 structure from 11:00 to 13:00 LT and a wave-number-4 structure around 15:00 LT. There is a sequential enhancement and recession among four sectors from east to west between 09:00 LT and 15:00 LT. (b) The seasonal dependence of PBO varies across sectors, particularly during the solstice months. The wavenumber spectral components of TEC along the longitudinal direction exhibit similar temporal patterns, suggesting that the atmospheric tides may modulate the local time and seasonal dependence of PBO. (c) Two EIA position models were developed. The model based on longitude and month can accurately capture the seasonal and spatial variations in the locations of peaks and troughs, with a mean residual of 0° and a standard deviation of 2.1°–2.3°.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119069","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":"Two- and Three-Dimensional Propagation Characteristics of Co-Volcanic Ionospheric Disturbances Induced by the 2022 Tonga Volcano Eruption Using Dense GNSS Network Data","authors":"Dengkui Mei,&nbsp;Xiaohong Zhang,&nbsp;Xiaodong Ren,&nbsp;Xuan Le,&nbsp;Hang Liu,&nbsp;Mohamed Freeshah","doi":"10.1029/2024JA032488","DOIUrl":"https://doi.org/10.1029/2024JA032488","url":null,"abstract":"<p>On 15 January 2022, the submarine volcano in Hunga Tonga-Hunga Ha’apai (hereinafter Tonga volcano) erupted at 04:14 universal time. This study investigated the two- and three-dimensional co-volcanic ionospheric disturbances (CVIDs) induced by the strong Tonga volcano. Based on dense Global Navigation Satellite System network data in Australia, the two-dimensional detrended total electron content maps were first generated by using the Savitzky-Golay filtering method. Using a compressed sensing-based computerized ionospheric tomography approach, the three-dimensional ionospheric electron densities were reconstructed. After the eruption, the distinctive CVIDs began to be mostly observed over southeastern Australia, about 4,000 km from the volcano. Two patterns of observable CVIDs, that is, fast-mode and slow-mode CVIDs, traveled outward from the Tonga volcano at speeds of 600–850 and 200–350 m/s, respectively. The slow-mode CVIDs were related to the Lamb and secondary gravity waves, while the fast-mode CVIDs were related to acoustic waves. Three-dimensional reconstruction results demonstrated that as the CVIDs propagated upward, the electron densities fluctuated at most altitude-longitude slices, and the wave-like propagating patterns were clearly observed around the peak ionospheric heights of 260–340 km. At the peak ionospheric height, the ionospheric parameters derived from the two ionosondes over Australia also detected similar wave-like features. Two-dimensional and three-dimensional observational evidence of the Tonga-induced CVIDs enhances research on volcanic eruption effects over the upper ionosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119036","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":"Relationship Between TEC Perturbations and Rayleigh Waves Associated With 2023 Turkey Earthquake Doublet","authors":"Huan Rao,&nbsp;Chieh-Hung Chen,&nbsp;Guojie Meng,&nbsp;Jing Liu,&nbsp;Yang-Yi Sun,&nbsp;Kai Lin,&nbsp;Yongxin Gao,&nbsp;Yuriy Rapoport,&nbsp;Fei Wang,&nbsp;Aisa Yisimayili,&nbsp;Shengjia Zhang","doi":"10.1029/2024JA033267","DOIUrl":"https://doi.org/10.1029/2024JA033267","url":null,"abstract":"<p>An earthquake doublet occurred in Turkey on 6 February 2023, with propagating Rayleigh waves triggering perturbations in the ionospheric total electron content (TEC) for both the M 7.8 earthquake (EQ7.8) and the M 7.5 earthquake (EQ7.5). A discrepancy between the velocities of TEC perturbations and Rayleigh waves has been noted, but its causes remain unresolved in previous studies. In this study, we calculated the velocities of TEC perturbations and the frequency-dependent velocities of Rayleigh waves, considering their intrinsic dispersive characteristics. To retrieve TEC, we utilized ground-based Global Navigation Satellite System (GNSS) data from geostationary Earth orbit (GEO) satellites to mitigate the effects of moving ionospheric pierce points (IPPs) from orbiting satellites. The results reveal that the velocities of TEC perturbations (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>2.60 km/s for EQ7.8 and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>2.77 km/s for EQ7.5) do not align with the velocities of Rayleigh waves across the entire frequency band (2.4–3.0 km/s for EQ7.8 and 2.6–3.5 km/s for EQ7.5). However, they are comparable within specific periods of 10–30 s due to dispersion effects for both EQ7.8 and EQ7.5. The dispersive Rayleigh waves, which exhibit significant amplification in the 10–30 s period range, are identified as the primary source of the pronounced coseismic TEC perturbations, particularly for EQ7.5.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118618","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":"Reliability of Matching AMPERE Field-Aligned Current Boundaries With SuperDARN Lower Latitude Ionospheric Convection Boundaries During Geomagnetic Storms","authors":"M.-T. Walach,&nbsp;A. R. Fogg,&nbsp;J. C. Coxon,&nbsp;A. Grocott,&nbsp;S. E. Milan,&nbsp;H. K. Sangha,&nbsp;K. A. McWilliams,&nbsp;S. K. Vines,&nbsp;M. Lester,&nbsp;B. J. Anderson","doi":"10.1029/2024JA033253","DOIUrl":"https://doi.org/10.1029/2024JA033253","url":null,"abstract":"<p>High-latitude ionospheric convection is a useful diagnostic of solar wind-magnetosphere interactions and nightside activity in the magnetotail. For decades, the high-latitude convection pattern has been mapped using the Super Dual Auroral Radar Network (SuperDARN), a distribution of ground-based radars which are capable of measuring line-of-sight (l-o-s) ionospheric flows. From the l-o-s measurements an estimate of the global convection can be obtained. As the SuperDARN coverage is not truly global, it is necessary to constrain the maps when the map fitting is performed. The lower latitude boundary of the convection, known as the Heppner-Maynard boundary (HMB), provides one such constraint. In the standard SuperDARN fitting, the HMB location is determined directly from the data, but data gaps can make this challenging. In this study we evaluate if the HMB placement can be improved using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), in particular for active time periods when the HMB moves to latitudes below <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>55</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $55{}^{circ}$</annotation>\u0000 </semantics></math>. We find that the boundary as defined by SuperDARN and AMPERE are not always co-located. SuperDARN performs better when the AMPERE currents are very weak (e.g., during non-active times) and AMPERE can provide a boundary when there is no SuperDARN scatter. Using three geomagnetic storm events, we show that there is agreement between the SuperDARN and AMPERE boundaries but the SuperDARN-derived convection boundary mostly lies <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>3</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${sim} 3{}^{circ}$</annotation>\u0000 </semantics></math> equatorward of the AMPERE-derived boundary. We find that disagreements primarily arise due to geometrical factors and a time lag in expansions and contractions of the patterns.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118647","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":"Significant East-West Electron Density Differences Occurring in Less Than 30° Longitude Over the Ocean During the Recovery Phase of a Strong Geomagnetic Storm in Solar Minimum","authors":"Jiawei Kuai,&nbsp;Qiaoqiao Ma,&nbsp;Tingting Yu,&nbsp;Kun Wu,&nbsp;Hao Sun,&nbsp;Yedan Zhang","doi":"10.1029/2024JA033549","DOIUrl":"https://doi.org/10.1029/2024JA033549","url":null,"abstract":"<p>We conducted observational studies of ionospheric responses to the geomagnetic storm on 12 May 2021. We selected three cases that the electron density altitude profiles observed by Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) exhibited significant longitudinal differences in less than 30° longitudes. These cases occurred over the Atlantic Ocean and during the storm's recovery phase. All three cases show relatively weaker variations on the west side between disturbed and quiet time (&lt;10%), while displaying pronounced positive/negative electron density variations on the east side (as large as 100%). GOLD and ICON observations illustrate that the thermospheric composition plays a minor role in the longitudinal differences, while neutral winds and disturbed electric fields make major contributions. Furthermore, significant longitudinal differences in E×B drift and neutral winds have also been observed, which will be part of the future work. This study provides unique insights into ionospheric responses within 30-degree longitude range over the ocean.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118460","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":"Tidally Driven Intra-Seasonal Oscillations in the Thermosphere From TIEGCM-ICON and Connections to the Madden-Julian Oscillation","authors":"Federico Gasperini,&nbsp;Astrid Maute,&nbsp;Houjun Wang,&nbsp;Owen McClung,&nbsp;Deepali Aggarwal,&nbsp;Komal Kumari","doi":"10.1029/2024JA033178","DOIUrl":"https://doi.org/10.1029/2024JA033178","url":null,"abstract":"&lt;p&gt;Recent evidence has revealed that strong coupling between the lower atmosphere and the thermosphere (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ &gt;} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;100 km) occurs on intra-seasonal (IS) timescales (&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;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 30–90 days). The Madden-Julian Oscillation (MJO), a key source of IS variability in tropical convection and circulation, influences the generation and propagation of atmospheric tides and is believed to be a significant driver of thermospheric IS oscillations (ISOs). However, limited satellite observations in the “thermospheric gap” (100–300 km) and challenges faced by numerical models in characterizing this region have hindered a comprehensive understanding of this connection. This study uses an Ionospheric Connection Explorer (ICON)-adapted version of the Thermosphere Ionosphere Electrodynamics General Circulation Model, incorporating lower boundary tides from Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) observations, to quantify the impact of the upward-propagating tidal spectrum on thermospheric ISOs and elucidate connections to the MJO. Thermospheric zonal and diurnal mean zonal winds exhibit prominent (&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;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 20 m/s) tidally driven ISOs throughout 2020–2021, largest at low latitudes &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;mn&gt;30&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; $(pm 30{}^{circ})$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; near 110–150 km altitude. Correlation analyses confirm a robust connection &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;mi&gt;r&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;0.6&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(r &gt; 0.6)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; between thermospheric ISOs, tides, and the MJO. Additionally, Hovmöller diagrams show eastward tidal propagation consistent with the MJO and concurrent Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations. This study demonstrates that vertically propagating tides play a crucial role in linking IS variability from the lower at","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118461","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":"The Formation Mechanism of Merged EIA During a Storm on 4 November 2021","authors":"Kun Wu,&nbsp;Liying Qian,&nbsp;Wenbin Wang,&nbsp;Xuguang Cai,&nbsp;Joseph M. Mclnerney","doi":"10.1029/2024JA032896","DOIUrl":"https://doi.org/10.1029/2024JA032896","url":null,"abstract":"<p>In this study, we conduct an in-depth analysis of Whole Atmosphere Community Climate Model-eXtended simulations to examine physical mechanisms of the formation and evolution of an equatorial ionization anomaly (EIA) merging phenomenon during a storm on 4 November 2021. A quantitative analysis reveals that the rapid decay of the EIA crests at their poleward sides at altitudes of ∼200–250 km plays a crucial role in the EIA merging during that day. This rapid decay is due to the fast recombination at low altitudes (∼200–250 km) as the plasma are transported downward by the westward disturbance dynamo electric field and poleward neutral winds during the storm. The results suggested EIA-merging is not merely northern and southern EIA crests moving together, but it involves a crucial rapid decay of the EIA crests at their poleward sides that descended to low altitudes (rapid recombination, ∼200–250 km), driven by regional electric fields and neutral winds. This study plays a crucial role in our understanding of the evolution and formation of the merged EIA on 4 November 2021 during the storm.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118700","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}