Journal of Geophysical Research: Space Physics最新文献

{"title":"Higher-Order Gravity Waves and Traveling Ionospheric Disturbances From the Polar Vortex Jet on 11–15 January 2016: Modeling With HIAMCM-SAMI3 and Comparison With Observations in the Thermosphere and Ionosphere","authors":"Sharon L. Vadas,&nbsp;David R. Themens,&nbsp;Joseph D. Huba,&nbsp;Erich Becker,&nbsp;Katrina Bossert,&nbsp;Larisa Goncharenko,&nbsp;Sophie J. Maguire,&nbsp;Cosme A. O. B. Figueiredo,&nbsp;Shuang Xu,&nbsp;V. Lynn Harvey,&nbsp;Nathaniel A. Frissell,&nbsp;Michael J. Molzen,&nbsp;Thomas J. Pisano,&nbsp;Grzegorz Nykiel","doi":"10.1029/2024JA033040","DOIUrl":"https://doi.org/10.1029/2024JA033040","url":null,"abstract":"<p>In Vadas et al. (2024, https://doi.org/10.1029/2024ja032521), we modeled the atmospheric gravity waves (GWs) during 11–14 January 2016 using the HIAMCM, and found that the polar vortex jet generates medium to large-scale, higher-order GWs in the thermosphere. In this paper, we model the traveling ionospheric disturbances (TIDs) generated by these GWs using the HIAMCM-SAMI3 and compare with ionospheric observations from ground-based Global Navigation Satellite System (GNSS) receivers, Incoherent Scatter Radars (ISR) and the Super Dual Auroral Radar Network (SuperDARN). We find that medium to large-scale TIDs are generated worldwide by the higher-order GWs from this event. Many of the TIDs over Europe and Asia have concentric ring/arc-like structure, and most of those over North/South America have planar wave structure and occur during the daytime. Those over North/South America propagate southward and are generated by higher-order GWs from Europe/Asia which propagate over the Arctic. These latter TIDs can be misidentified as arising from geomagnetic forcing. We find that the higher-order GWs that propagate to Africa and Brazil from Europe may aid in the formation of equatorial plasma bubbles (EPBs) there. We find that the simulated GWs, TIDs and EPBs agree with EISCAT, PFISR, GNSS, and SuperDARN measurements. We find that the higher-order GWs are concentrated at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>60</mn>\u0000 <mo>−</mo>\u0000 <mn>90</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $60-90{}^{circ}$</annotation>\u0000 </semantics></math>N at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>z</mi>\u0000 <mspace></mspace>\u0000 <mo>≥</mo>\u0000 </mrow>\u0000 <annotation> $z ge $</annotation>\u0000 </semantics></math> 200 km, in agreement with GOCE and CHAMP data. Thus the polar vortex jet is important for generating TIDs in the northern winter ionosphere via multi-step vertical coupling through GWs.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119924","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":"Overall Morphology of Prominent Zonal Differences in Low Latitude Ionosphere","authors":"Yuyan Yang,&nbsp;Libo Liu,&nbsp;Wenbo Li,&nbsp;Xiukuan Zhao,&nbsp;Yiding Chen,&nbsp;Huijun Le,&nbsp;Ruilong Zhang,&nbsp;Jianyong Lu","doi":"10.1029/2024JA033165","DOIUrl":"https://doi.org/10.1029/2024JA033165","url":null,"abstract":"<p>This paper reports the overall morphology of prominent zonal differences in total electron content (TEC) data from Beidou geostationary orbit (GEO) satellites in the low latitude ionosphere over the Asia sector. Using GEO TEC observations from the GXZY receiver (26.2°N, 110.6°E) from 1 November 2019 to 30 November 2022, 64 prominent zonal difference events under geomagnetic quiet conditions were selected. We clarify the global longitude structures corresponding to these prominent zonal difference events at low latitudes through the global TEC products from the Massachusetts Institute of Technology. The structures that can cause the prominent zonal difference features in GEO TEC data are mainly divided into large-scale wave-like structures and featured regional structures. Among them, 19 cases of prominent zonal difference features were caused by large-scale wave-like structures, and 45 cases were caused by regional longitude structures. Prominent zonal differences generated from Large-scale wave-like structures are explained by the day-to-day variation of wave components, which creates an amplitude superposition and amplifies the crest intensity in a region. The featured regional structures cover a longitudinal range of about 10°–30°. In addition, we discussed the possible reasons for this small longitudinal structure by utilizing plasma drift velocity data at the magnetic equator from the Ionospheric Connection Explorer mission. The delicate longitude structures of vertical and zonal plasma drift likely contribute to the prominent zonal difference features in certain events.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119925","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 the Two-Dimensional Propagation of Whistler-Mode Chorus Waves in the Magnetic Peaks","authors":"Bopu Feng,&nbsp;Xiongdong Yu,&nbsp;Haimeng Li,&nbsp;Meng Zhou,&nbsp;Rongxin Tang,&nbsp;Zhihai Ouyang,&nbsp;Ying Xiong,&nbsp;An Yuan,&nbsp;Wenqian Zou,&nbsp;Yingqiao Cheng","doi":"10.1029/2024JA033383","DOIUrl":"https://doi.org/10.1029/2024JA033383","url":null,"abstract":"<p>Recent studies have shown that chorus waves can be guided by magnetic peaks based on one-dimensional theories and simulations. Despite these findings, such ducting propagation within the inner magnetosphere remains unconfirmed. In this research, we conduct detailed ray tracing simulations to explore the two-dimensional behavior of chorus waves in regions characterized by magnetic peaks. Our findings demonstrate that chorus waves can indeed be guided by magnetic peaks, undergoing repeated reflections on both sides of the peak. Additionally, we discuss the physical mechanisms responsible for these repetitive reflections, offering deeper insights into the process. To further enrich our analysis, we performed a parameter analysis to study how different wave frequencies and initial locations influence the propagation characteristics of chorus waves. The results provide a more comprehensive understanding of how whistler-mode waves propagate within the magnetosphere, enhancing our knowledge of wave-particle interactions and the dynamics of space plasma environments.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119825","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":"Observations of a Throat Aurora Directly Driven by Magnetosheath High-Speed Jet","authors":"Zhiwei Wang,&nbsp;Desheng Han,&nbsp;Xiangcai Chen,&nbsp;Run Shi,&nbsp;Shangchun Teng,&nbsp;Jian Zhang,&nbsp;Jianjun Liu,&nbsp;Qiang Zhang,&nbsp;Huixuan Qiu","doi":"10.1029/2024JA033276","DOIUrl":"https://doi.org/10.1029/2024JA033276","url":null,"abstract":"<p>Throat aurora, characterized as an auroral structure bulging out from equatorward boundary of the auroral oval, has been confirmed to correspond to magnetopause crack. Previous studies suggested that the occurrence of throat aurora is influenced by both magnetospheric internal and external factors. It remains unclear if a single external factor, like a magnetosheath high-speed jet (HSJ), can directly drive throat aurora or not. Through coordinated magnetosheath and ground-based observations, we have established a reliable connection between throat auroras observed on the ground and successive HSJs observed in the magnetosheath, suggesting that HSJ can indeed directly induce throat aurora. Upon further investigation, we found that this HSJ-induced throat aurora exhibited highly dynamic properties with a shorter duration compared to previously reported convection-aligned long-duration throat auroras. These findings suggest the involvement of distinct mechanisms in throat aurora generation, emphasizing the necessity for a comprehensive classification to better comprehend this phenomenon.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119824","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 Characteristics and Simulation of Sporadic E Layers in Ascending and Descending Phases of the Solar Cycle at Mid-Latitude Stations","authors":"Yabin Zhang,&nbsp;Huaiyun Peng,&nbsp;Ruimin Jin,&nbsp;Haiying Li,&nbsp;Yanli Hu,&nbsp;Panpan Ban,&nbsp;Bin Xu,&nbsp;Tong Xu,&nbsp;Haisheng Zhao,&nbsp;Jiajing Wu,&nbsp;Yaoyu Tian,&nbsp;Shouzhi Xie,&nbsp;Jian Wu","doi":"10.1029/2024JA033356","DOIUrl":"https://doi.org/10.1029/2024JA033356","url":null,"abstract":"<p>Most of the attention was paid to the correlation between Sporadic E (Es) layers and solar activity, and conflicting conclusions were obtained in previous research. For the first time, we analyze the influence of solar activity on the number of Es layer traces (Es layers with a certain duration and intensity), the lifetime and descent velocity of the descending Es layer traces, and the results have been explained using simulation based on windshear theory and Lomb-Scargle (LS) spectral analysis. A statistical analysis of Es layers observed in ascending (2010–2012) and descending (2016–2018) phases of the solar cycle is presented at three different mid-latitude stations of Kuming (25.5°N, 103.8°E), Lanzhou (36.1°N, 103.9°E) and Urumqi (43.8°N, 87.6°E) in China region. The observation results indicate that the occurrence rate, height distribution and the number of the Es layer traces are all influenced by solar activity, indicating that they are negatively correlated with solar activity. The simulation, spectral analysis, and observations reveal that the lifetime and descent velocity of the descending Es layer traces are mainly modulated by semidiurnal and diurnal tides, but are less affected by solar activity. The predominant oscillations of the Es layer are identified using LS spectral analysis. The spectral analysis reveals that the modulation of diurnal tide waves on Es layers dominates at lower mid-latitudes, and that of semidiurnal tide waves dominates at higher latitudes. The results also confirm the modulation of planetary waves on Es layers at different mid-latitudes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119876","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":"Simulation for the Calibration of Radiation Housekeeping Monitor Onboard BepiColombo/MMO and Application to the Inner Heliosphere Exploration","authors":"G. Kinoshita,&nbsp;H. Ueno,&nbsp;G. Murakami,&nbsp;M. Pinto,&nbsp;K. Yoshioka,&nbsp;Y. Miyoshi","doi":"10.1029/2024JA033147","DOIUrl":"https://doi.org/10.1029/2024JA033147","url":null,"abstract":"<p>Although primarily a housekeeping instrument for measuring ambient radiation, the Solar Particle Monitor (SPM) onboard BepiColombo can measure high-energy particles, making it useful for observing phenomena such as galactic cosmic rays and Solar Energetic Particles (SEPs). However, it only records time-series data of particle energy loss and counts, which requires characterization by radiation simulation for scientific analysis. In this study, a physical model of the SPM was constructed using the “Geant4” radiation simulation toolkit to investigate its response to charged particles. The probability density functions were derived from the response functions to indicate the proportion of particles in each energy range among the SPM counts. Finally, we inverse-calculated the flux from the counts in the corresponding energy ranges. We applied this method to data from the terrestrial radiation belt and SEPs in March 2022. The results agreed with the empirical radiation belt model and another instrument onboard BepiColombo, demonstrating the validity of the method. This study highlights the potential for scientific applications of housekeeping instruments and suggests the broader use of similar methods on other missions for expanding inner heliosphere multi-point exploration.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033147","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119840","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":"Classifying the Magnetosheath Using Local Measurements From MMS","authors":"I. Svenningsson,&nbsp;E. Yordanova,&nbsp;Y. V. Khotyaintsev,&nbsp;M. André,&nbsp;G. Cozzani","doi":"10.1029/2024JA033272","DOIUrl":"https://doi.org/10.1029/2024JA033272","url":null,"abstract":"<p>The Earth's magnetosheath is a dynamic region of shocked solar wind plasma downstream of the bow shock. Depending on the upstream magnetic field orientation, the magnetosheath usually has one of two distinct configurations: a more variable magnetosheath with strong fluctuations and structures propagating from upstream to downstream, or a more stationary magnetosheath characterized by compression and high ion temperature anisotropy. The more variable magnetosheath is usually observed for quasi-parallel shocks (the angle between the shock normal and the upstream magnetic field <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>θ</mi>\u0000 <mtext>Bn</mtext>\u0000 </msub>\u0000 <mo>&lt;</mo>\u0000 <mn>45</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${theta }_{text{Bn}}&lt; 45{}^{circ}$</annotation>\u0000 </semantics></math>), but the limit can vary for <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>40</mn>\u0000 <mo>°</mo>\u0000 <mo>≤</mo>\u0000 <msub>\u0000 <mi>θ</mi>\u0000 <mtext>Bn</mtext>\u0000 </msub>\u0000 <mo>≤</mo>\u0000 <mn>70</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $40{}^{circ}le {theta }_{text{Bn}}le 70{}^{circ}$</annotation>\u0000 </semantics></math>. These differences facilitate studies of how different plasma environments affect various processes such as turbulence and heating, and these require an accurate magnetosheath classification. Since <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>θ</mi>\u0000 <mtext>Bn</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${theta }_{text{Bn}}$</annotation>\u0000 </semantics></math> can rarely be determined correctly in the absence of upstream monitors, local measurements have been suggested to classify the magnetosheath. However, this has not yet been verified for Magnetospheric Multiscale (MMS) data. We investigate this approach with MMS using locally measured magnetic field variability, ion temperature anisotropy, and suprathermal ion flux. We find the more variable magnetosheath at normalized magnetic fluctuations above 0.29 and ion temperature anisotropy below 0.18. We also find that the suprathermal ion flux can complement the classification given that MMS burst-mode data is used. Our findings provide a method to determine the magnetic connectivity of the magnetosheath with the upstream solar wind in the case of MMS and classify the downstream region into different configurations.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033272","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119529","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 “Zebra Stripes” of Relativistic Electrons Unveiled by CIRBE/REPTile-2 Measurements and Test Particle Simulations","authors":"Yang Mei,&nbsp;Xinlin Li,&nbsp;Declan O’Brien,&nbsp;Zheng Xiang,&nbsp;Hong Zhao,&nbsp;Theodore Sarris,&nbsp;Benjamin Hogan,&nbsp;David Brennan,&nbsp;Michael Temerin","doi":"10.1029/2024JA033187","DOIUrl":"https://doi.org/10.1029/2024JA033187","url":null,"abstract":"<p>Drift periodic echoes of electrons in the inner belt appear as structured bands in energy spectrograms, also known as “zebra stripes”. Such phenomenon is normally observed at energies from 10s of keV to ∼250 keV. We report multiple series of zebra stripes of relativistic electrons observed by the recent Colorado Inner Radiation Belt Experiment (CIRBE) CubeSat. The high energy resolution measurements taken by the REPTile-2 (Relativistic Electron and Proton Telescope integrated little experiment-2) instrument onboard CIRBE show that zebra stripes of radiation belt electrons can be observed from 300 keV to &gt;1 MeV, crossing the <i>L</i> range from 1.18 to &gt;3, from quiet times to storm times. Through test particle simulations, we show that a prompt electric field with a peak amplitude ∼5 mV/m in near-Earth space can trigger zebra stripes of relativistic electrons. Azimuthal inhomogeneity of electron distribution caused by the prompt electric field modulates the electron energy spectrum by energy-dependent drift phases to form zebra stripes. Though zebra stripes are observed in both belts, they tend to last longer and appear more frequently in the inner belt. Zebra stripes in the outer belt will have a shorter lifetime due to more perturbations there, including energy and pitch-angle diffusion, which diminish the structure. This study demonstrates the important role of electric fields in the dynamics of relativistic electrons and contributes to the understanding of the mechanisms creating and diminishing zebra stripes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119262","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":"Traveling Ionospheric Disturbances With Huge Semicircular and Circular Structures Triggered by Two Rocket Launches Over China","authors":"Haiyong Xie,&nbsp;Guozhu Li,&nbsp;Feng Ding,&nbsp;Xiukuan Zhao,&nbsp;Lianhuan Hu,&nbsp;Wenjie Sun,&nbsp;Yu Li,&nbsp;Yi Li,&nbsp;Guofeng Dai,&nbsp;Jianfei Liu,&nbsp;Libo Liu,&nbsp;Baiqi Ning","doi":"10.1029/2024JA033370","DOIUrl":"https://doi.org/10.1029/2024JA033370","url":null,"abstract":"<p>Rocket-launching can trigger traveling ionospheric disturbances (TIDs) which often show V-shaped structures. Using a dense Global Navigation Satellite System total electron content (TEC) receiver network, we investigated the ionospheric response to the waves triggered by the launches of Long March (LM) series of rockets, the LM-2D on 30 March 2023 and LM-6A on 10 September 2023. Results show that during the two launches, large ionospheric holes and TIDs with unusual semicircular and circular structures were observed. The ionospheric disturbances traveled for a distance of more than 1,500 km with amplitudes gradually decreased from about 0.1 to 0.03 TEC unit. The period and horizontal speed of disturbances were ∼7–8 min and around 700–800 m/s, respectively, which fell into the acoustic mode. We suggest that the TIDs were induced by shock acoustic waves (SAWs). The semicircular and circular structures could be attributed to the rocket flight tilt angle and the corresponding altitude of conic SAWs.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119273","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":"Simulations of Optical Emissions in Io's Plasma Torus","authors":"Edward G. Nerney,&nbsp;Fran Bagenal,&nbsp;Carl Schmidt","doi":"10.1029/2024JA033232","DOIUrl":"https://doi.org/10.1029/2024JA033232","url":null,"abstract":"<p>The Io plasma torus in Jupiter's magnetosphere, dominated by sulfur and oxygen ions from Io's volcanism, exhibits complex radial and azimuthal structures and significant temporal variability. This study analyzes ground-based optical emission data from the Dual Imaging Spectrograph on the 3.5 m telescope at Apache Point Observatory (APO). We deduce variability and determine steady-state radial conditions by combining 30 nights of observations from 2013 to 2018 and co-adding dawn and dusk profiles. The results of a “Cubic-cm” spectral emission model are compared with forward modeling techniques to account for projection effects and line-of-sight (LOS) integration. This study provides the first detailed characterization of local conditions within the ribbon, gap region, and cold torus from remote sensing of the major Io plasma torus species (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>S</mi>\u0000 <mo>+</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{S}}^{+}$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>S</mi>\u0000 <mrow>\u0000 <mo>+</mo>\u0000 <mo>+</mo>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{S}}^{++}$</annotation>\u0000 </semantics></math>, and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>O</mi>\u0000 <mo>+</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{O}}^{+}$</annotation>\u0000 </semantics></math>). We find that electron and ion densities in the cold torus are significantly lower than previous Voyager 1 PLS measurements, consistent with later studies. Electron temperatures in the cold torus align with Voyager PLS data, while those in the warm torus are lower than expected from Cassini UVIS and more consistent with contemporaneous Hisaki observations. Key findings include a shift of the cold torus toward Jupiter and a larger gap region, with ribbon locations remaining stable. The electron density profiles show a shallower decline with radial distance in the warm torus than previously reported, highlighting the variability within the Io plasma torus and the challenges of non-uniqueness in fitting plasma parameters determined via remote sensing.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033232","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119170","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}