Journal of Geophysical Research: Space Physics最新文献

{"title":"The Transmission of Pc 3 Waves From the Foreshock Into the Earth's Magnetosphere: 3D Global Hybrid Simulation","authors":"Jicheng Sun,&nbsp;Junyi Ren,&nbsp;Quanming Lu,&nbsp;Beichen Zhang,&nbsp;Huigen Yang","doi":"10.1029/2024JA033007","DOIUrl":"https://doi.org/10.1029/2024JA033007","url":null,"abstract":"<p>Although initially it was presumed that foreshock waves would propagate directly into the dayside magnetosphere, observational evidence for sinusoidal Pc3 waves in the downstream of quasi-parallel shocks is scarce. The transmission of these waves from the foreshock into the magnetosphere remains uncertain. In this paper, we employ a 3D global hybrid simulation at a realistic scale to explore the generation and transmission of the dayside ULF waves under a radial interplanetary magnetic field. Our findings demonstrate that the Pc3 waves are self-consistently generated in the foreshock region and then transmitted into the magnetosheath and magnetosphere. In the foreshock, the waves are excited at approximately 25 mHz and exhibit right-handed helicity in the plasma frame, characterizing them as quasi-parallel fast magnetosonic waves. In the magnetosphere, the fluctuating magnetic field is mainly parallel to the background magnetic field, which indicates the dominant wave modes are compressional. Fluctuations in the magnetosheath show a broader spectrum (10–100 mHz) compared to those in the magnetosphere and foreshock, potentially explaining the little observation of sinusoidal Pc3 waves in the magnetosheath. Additionally, only lower frequency compressional waves (below 30 mHz) are effectively transmitted into the dayside magnetosphere. Our simulation provides critical insights into the interactions between the solar wind and Earth's magnetosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525208","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":"Latitudinal Distribution of Dayside Magnetospheric Currents Based on Cluster Observations","authors":"Yingshuai Du,&nbsp;Wenlong Liu,&nbsp;Dianjun Zhang,&nbsp;Xin Tan,&nbsp;Malcolm W. Dunlop","doi":"10.1029/2024JA032943","DOIUrl":"https://doi.org/10.1029/2024JA032943","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Based on the curlometer method, we calculate the azimuthal component of the current density from nearly 19 years of Fluxgate Magnetometer (FGM) data of Cluster and investigate its latitudinal distribution in the dayside noon sector (09:00–15:00 magnetic local time, MLT). A crossing event in the noon meridian plane shows an unexpected eastward current at a geocentric distance of 8 <i>R</i>_E, away from the equator with latitudes of 30–40°. Further statistical results of the current distribution show that, the topology of the current can be radially divided into the inner and outer branches over the whole <i>r</i>_<i>xy</i> − <i>z</i> plane (<i>r</i>_<i>xy</i> = <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msqrt>\u0000 <mrow>\u0000 <msup>\u0000 <mi>x</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 <mo>+</mo>\u0000 <msup>\u0000 <mi>y</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 </msqrt>\u0000 </mrow>\u0000 <annotation> $sqrt{{x}^{2}+{y}^{2}}$</annotation>\u0000 </semantics></math> and <i>z</i> are in solar magnetic (SM) coordinates), with the separation point of these two branches at a geocentric distance of about 8 <i>R</i>_E. The current variations of the inner and outer branches are different under different Kp, solar wind flow speed <i>V</i>_<i>sw</i>, and solar wind dynamic pressure <i>P</i>_<i>dyn</i>. It is shown that the current densities in both the inner and outer branches increase significantly with the Kp. High solar wind dynamic pressure enhances the current density of the outer branch, while high solar wind speed, on the contrary, enhances that of the inner branch. The formation of the outer branch may be related to the anisotropy of plasma pressure.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525192","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":"Differential Delay of Ordinary and Extraordinary Modes of Transionospheric Radio Waves","authors":"Kuldeep Pandey,&nbsp;E. Ceren Kalafatoglu Eyiguler,&nbsp;Robert G. Gillies,&nbsp;Donald W. Danskin,&nbsp;Daniel D. Billett,&nbsp;Andrew W. Yau,&nbsp;Glenn C. Hussey","doi":"10.1029/2024JA032798","DOIUrl":"https://doi.org/10.1029/2024JA032798","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>The terrestrial ionosphere is a birefringent medium that allows radio waves to propagate in two modes: the ordinary (O-mode) and the extraordinary (X-mode). A difference in the index of refraction of the two modes results in differential delay (mode delay) between the O- and X-modes of radio waves propagating through the ionosphere. Mode delays of transionospheric high frequency radio waves are determined using the Radio Receiver Instrument (RRI) onboard the Enhanced Polar Outflow Probe (e-POP) on the CASSIOPE/Swarm-E satellite. Experiments between RRI and the SuperDARN radar at Saskatoon, Canada show large variabilities in mode delays. The mode delays are nearly constant in some experiments but other experiments have large variations. The mode delay observations could not be explained by the distance between the e-POP satellite and the radar, the foF2 values along the satellite track, nor whether the satellite track was across or along a SuperDARN radar beam. A combination of RRI observations and ray-trace modeling are used to investigate the mode delay of transionospheric radio waves.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524912","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":"H+, He+, He++, O++, N+ EMIC Wave Occurrence and Its Dependence on Geomagnetic Conditions: Results From 7 Years of Van Allen Probes Observations","authors":"M. E. Usanova,&nbsp;L. A. Woodger,&nbsp;L. W. Blum,&nbsp;R. E. Ergun,&nbsp;C. Girard,&nbsp;D. L. Gallagher,&nbsp;R. M. Millan,&nbsp;J. G. Sample,&nbsp;A. T. Johnson,&nbsp;I. R. Mann","doi":"10.1029/2024JA032627","DOIUrl":"https://doi.org/10.1029/2024JA032627","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Electromagnetic ion cyclotron (EMIC) waves are believed to play an important role in the dynamics of the inner magnetosphere, including the ring current, the radiation belts and potentially, the cold plasma. In this work, we investigate their occurrence in the magnetosphere and the geomagnetic and solar wind conditions which lead to their excitation. We use an automated detection algorithm of EMIC waves observed by Van Allen Probes over the entire mission duration between 2012 and 2019. Consistent with earlier studies, we find that the H⁺ band occurrence maximizes in the dayside magnetosphere during enhancements of solar wind dynamic pressure. Both the H⁺ and He⁺ band are also generated along the duskside magnetosphere during disturbed geomagnetic conditions. In addition, to H⁺ and He⁺ bands commonly surveyed, we investigate the occurrence of H⁺ waves above and below 0.5 H⁺ gyrofrequency, as well as wave occurrence in the N⁺ and O⁺⁺ bands. Most H⁺ waves are observed in the band below 0.5f_H+. We find several events in the N⁺ band, indicative of their very low occurrence. The O⁺⁺ band is observed during disturbed geomagnetic conditions and high solar wind dynamic pressure at low L-shells. Its radial localization coincides with the O⁺⁺ torus. This study provides a comprehensive picture of EMIC wave distribution and insight into ion composition in the inner magnetosphere during variable geomagnetic conditions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524914","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":"Investigation of Thermospheric Response to Geomagnetic Storms Using GITM-OVATION Prime and -FTA Model With Comparison to GOLD and SABER Observations","authors":"Atishnal Elvin Chand,&nbsp;George Bowden,&nbsp;Melrose Brown","doi":"10.1029/2023JA031820","DOIUrl":"https://doi.org/10.1029/2023JA031820","url":null,"abstract":"&lt;p&gt;Global Ionosphere Thermosphere Model (GITM) results have been compared with measurements from Global-scale observations of the limb and disk (GOLD) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). For the first time, GOLD-derived exospheric temperature and column-integrated &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}/mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; ratio measurements have been used to validate GITM model results. We examine two geomagnetic storm events for which we drive GITM with space weather conditions to understand how well the model reproduces the thermospheric responses to geomagnetic activity. In this paper, a recently developed auroral model, the Feature Tracking of Aurora (FTA) model, has been employed to calculate auroral electron precipitation in GITM (GITM w/FTA), and results are compared with the OVATION prime (OP) driven GITM model (GITM w/OP). GITM w/FTA simulated temperature, neutral density, and nitric oxide (NO) density are generally higher compared to the GITM w/OP model. During the geomagnetic storm, the GITM model and GOLD-derived exospheric temperature agree between &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;mn&gt;0&lt;/mn&gt;\u0000 &lt;mo&gt;°&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} 0{}^{circ}$&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;mn&gt;5&lt;/mn&gt;\u0000 &lt;mo&gt;°&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $5{}^{circ}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;N latitude in the equatorial region. GOLD measurements show strong &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}/mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; peaks on either side of the equator during the geomagnetic storm period, which is also observed in our model results. The NO cooling peaks estimated by GITM models are &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","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JA031820","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524776","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":"Impact Pattern of Energetic Particle Precipitation on Polar Mesospheric Ozone","authors":"Yuting Wang,&nbsp;Hui Li,&nbsp;Chi Wang","doi":"10.1029/2024JA032877","DOIUrl":"https://doi.org/10.1029/2024JA032877","url":null,"abstract":"<p>The upper atmosphere of polar regions exhibits two distinct patterns of energetic particle precipitation that can lead to ozone destruction by ionizing the atmosphere: one is the energetic proton precipitation in the polar cap region during solar proton events (SPEs), and the other is the energetic electron precipitations (EEPs) in the auroral oval region from the radiation belt. In this study, we conduct case studies and statistical analyses of ozone observations from the Aura satellite to present the quantitative difference in the impact patterns of SPEs and EEPs on polar mesospheric ozone. According to our statistical analysis of 13 SPEs and 19 EEPs during the MLS time frame, the magnitude of ozone depletion during SPEs is greater than during EEPs. The ozone depletion during SPEs is more pronounced at higher geomagnetic latitudes and negatively correlates with the proton flux, while during EEPs the ozone depletion is more in favor of the geomagnetic latitude band of 60–70° but independent of the electron count rates. In addition, hydroxyl enhancement also exhibits different patterns during SPEs and EEPs, similar to that of ozone depletion. This study further validates the physical link between the magnetosphere and atmosphere and promotes our understanding of the solar influence on Earth's climate.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524775","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 and Thermospheric Effects of Hurricane Grace in 2021 Observed by Satellites","authors":"Ayden L. S. Gann,&nbsp;Erdal Yiğit","doi":"10.1029/2024JA032933","DOIUrl":"https://doi.org/10.1029/2024JA032933","url":null,"abstract":"<p>Effects of Hurricane Grace in August 2021 are studied in the thermosphere and ionosphere, using data from the COSMIC-2, ICON, and GOLD satellites. Significant impacts on electron density, thermospheric winds, and temperature are observed after the onset of the hurricane, compared to the pre-hurricane phase. Comparison of the observations during the hurricane with the ones during a non-hurricane year clearly provides further evidence for substantial hurricane-induced thermospheric and ionospheric changes. We reveal an enhancement in electron density during the hurricane's rapid intensification and pronounced changes in thermospheric winds. Additionally, the low-latitude thermosphere exhibits considerable warming of up to 70 K around 150 km during this period. These changes highlight the long-range vertical coupling mechanisms between hurricanes and the upper atmosphere, and provide valuable insights into the profound influence of meteorological events on upper atmospheric dynamics, emphasizing the need for further exploration.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032933","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Latitudinal Characteristics of the Post-Sunset Enhancements in Ionospheric Electron Density During the Geomagnetic Quiet Period in May 2021 Over East-Asian Region","authors":"Honglian Hao,&nbsp;Biqiang Zhao,&nbsp;Xinan Yue,&nbsp;Feng Ding,&nbsp;Guozhu Li,&nbsp;Wenjie Sun,&nbsp;Zhipeng Ren,&nbsp;Libo Liu","doi":"10.1029/2024JA033047","DOIUrl":"https://doi.org/10.1029/2024JA033047","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>This study investigated the latitudinal variations of post-sunset enhancements in the ionospheric electron density during the geomagnetic quiet period in May 2021 with a combination of high-precision ionospheric parameters obtained from four ionosondes, Beidou geostationary satellite (BD-GEO) receiver network and Sanya incoherent scatter radar (SYISR). We identified four categories of post-sunset enhancement phenomena (Types 1–4), each with unique spatial and temporal evolutions, yet uniformly accompanied by a decrease in hmF2. Measurements of plasma drift vector velocities from SYISR and hmF2 gradients across various latitudes provided pivotal insights, confirming that the ionospheric post-sunset enhancements can result from downward plasma motion due to westward electric field, downward field-aligned drift, or a combination of both. For Type 1, dominated by field-aligned drift, plasma density enhancements not only intensify at low latitudes but may also extend to mid-latitudes, exhibiting a distinct temporal delay with increasing latitude. In contrast, Type 4, primarily driven by the westward electric field, is characterized by modest increases in plasma density confined to localized low-latitude regions, with no observable latitudinal time delay in the peak of enhancements. Types 2 and 3, which are subject to the combined influence of the westward electric field and field-aligned drift, exhibit plasma density increases at certain low-latitude areas, with Type 2 presenting a delayed pattern and Type 3 showing none with rising latitude. Meanwhile, neutral winds can partially account for the observed post-sunset enhancement from low to middle latitudes. These findings offer new insights into the factors influencing ionospheric behavior after sunset.</p>\u0000 </section>\u0000 </div>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524897","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 Non-Migrating DE3 Tide Response to the MJO Phenomenon at the MLT Altitudes","authors":"Xing Li,&nbsp;Zhipeng Ren,&nbsp;Jinbin Cao","doi":"10.1029/2024JA032792","DOIUrl":"https://doi.org/10.1029/2024JA032792","url":null,"abstract":"<p>Based on TIMED/SABER temperature observations and the Real-Time Multivariate Madden-Julian Oscillation (MJO) Index, for the first time, we discussed the daily resolution non-migrating DE3 temperature tide response to the MJO phenomenon during MJO phases between ±45° latitude from 2003 to 2012 in the Mesosphere and Lower Thermosphere (MLT) region. We found: (a) The DE3 tide significantly depends on different MJO phases in the four seasons above 100 km altitude. The DE3 tidal phase exhibits varying responses to the different MJO phases. (b) The DE3 tide response to the MJO phenomenon is stronger at the solstices than at the equinoxes, and the response at the June solstices is stronger. (c) The symmetric component of the DE3 response to the MJO phenomenon is stronger than the asymmetric component. In summary, the daily resolved DE3 tide response to the MJO phenomenon, especially the DE3 tidal phase dominates certain seasonal characteristics and symmetry in the MLT region.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524896","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":"Characterizing the Magnetic and Plasma Environment Upstream of Ganymede","authors":"A. Santos,&nbsp;N. Achilleos,&nbsp;D. Millas,&nbsp;W. Dunn,&nbsp;P. Guio,&nbsp;C. S. Arridge","doi":"10.1029/2024JA032689","DOIUrl":"https://doi.org/10.1029/2024JA032689","url":null,"abstract":"<p>We present an application of the latest UCL-AGA magnetodisc model (MDISC) to the study of the magnetic and plasma conditions in the near-Ganymede space. By doing this, we provide a comparison with measurements from Juno's most recent flyby of the Jovian moon, perijove 34 (PJ34). We find good agreement between the model results and the magnetometer data, pointing toward a hot plasma index value <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>K</mi>\u0000 <mi>h</mi>\u0000 </msub>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> ${K}_{h}=$</annotation>\u0000 </semantics></math> (2.719<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math>0.024)<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation> ${times} $</annotation>\u0000 </semantics></math>10⁷ Pa m T⁻¹ and an effective magnetodisc radius <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>r</mi>\u0000 <mtext>max</mtext>\u0000 </msub>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> ${r}_{text{max}}=$</annotation>\u0000 </semantics></math> (79.5<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math>1.1) Jupiter radii for the Jovian magnetosphere, for the duration of the trajectory, suggesting a configuration with middling levels of expansion. We also predict the plasma conditions observed by Juno during the same flight-path, as well as the typical conditions over the orbit of Ganymede, with the magnetic and hot plasma pressures assuming dominant roles. Finally, these results are compared with functional fits of a compilation of Galileo flyby data obtained in the vicinity of Ganymede's orbit, suggesting Juno experienced somewhat similar conditions, despite a systematic overestimation in magnetic field intensity in the near-Ganymede space.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451253","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}