Journal of Geophysical Research: Space Physics最新文献

{"title":"Multi-Event Analysis of STEVE, SAR Arc, and Red/Green Arc at Subauroral Latitudes Using Data From Ground Optical and Radio Instruments and the Arase and Van Allen Probes Satellites","authors":"Rei Sugimura,&nbsp;Kazuo Shiokawa,&nbsp;Yuichi Otsuka,&nbsp;Shin-ichiro Oyama,&nbsp;Arto Oksanen,&nbsp;Martin Connors,&nbsp;Akira Kadokura,&nbsp;Igor Poddelsky,&nbsp;Nozomu Nishitani,&nbsp;Simon G. Shepherd,&nbsp;J. Michael Ruohoniemi,&nbsp;Charles Smith,&nbsp;Harlan Spence,&nbsp;Geoff Reeves,&nbsp;Herbert O. Funsten,&nbsp;Yoshizumi Miyoshi,&nbsp;Iku Shinohara,&nbsp;Yoshiya Kasahara,&nbsp;Fuminori Tsuchiya,&nbsp;Atsushi Kumamoto,&nbsp;Atsuki Shinbori,&nbsp;Kazushi Asamura,&nbsp;Shoichiro Yokota,&nbsp;Yoichi Kazama,&nbsp;C.-W. Jun,&nbsp;Shiang-Yu Wang,&nbsp;Sunny W. Y. Tam,&nbsp;Tzu-Fang Chang,&nbsp;Bo-Jhou Wang,&nbsp;Satoshi Kasahara,&nbsp;Kunihiro Keika,&nbsp;Tomoaki Hori,&nbsp;Ayako Matsuoka","doi":"10.1029/2024JA032793","DOIUrl":"https://doi.org/10.1029/2024JA032793","url":null,"abstract":"<p>Strong Thermal Emission Velocity Enhancement (STEVE) is a latitudinally narrow, purple-band emission observed at subauroral latitudes. Stable Auroral Red (SAR) arcs characterized by major red emission, and red/green arcs with both red and green emissions also occur at subauroral latitudes. Characteristics of magnetospheric source plasma and electromagnetic fields of these three types of arcs have not been fully understood because of the limited conjugate observations between magnetosphere and the ground. In this study, we report 11 conjugate observations (2 STEVEs, 7 SAR arcs, and 2 red/green arcs), using all-sky images obtained at seven ground stations over more than four years from January 2017 to April 2021 and magnetospheric satellites (Arase and Van Allen Probes). We found that, in the inner magnetosphere, the source region of STEVEs and red/green arcs were located outside the plasmasphere, and that of the SAR arc was in the region of spatial overlap between the plasmasphere and ring current region. Electromagnetic waves at frequencies below 1 Hz were observed for STEVEs and red/green arcs. SuperDARN radar data showed a strong westward plasma flow in the ionosphere, especially during STEVE events, whereas the plasma flows associated with SAR arcs and red/green arcs were generally weaker and variable. The STEVE and SAR arc can appear simultaneously at slightly different latitudes and STEVEs and red/green arcs can transform into SAR arcs. These first comprehensive ground-satellite measurements of three types of subauroral-latitude auroras increase our understanding on similarlity, differences, and coupling of these auroras in the ionosphere and the magnetosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362411","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":"A New Electron and Proton Radiation Belt Identified by CIRBE/REPTile-2 Measurements After the Magnetic Super Storm of 10 May 2024","authors":"Xinlin Li,&nbsp;Zheng Xiang,&nbsp;Yang Mei,&nbsp;Declan O'Brien,&nbsp;David Brennan,&nbsp;Hong Zhao,&nbsp;Daniel N. Baker,&nbsp;Michael A. Temerin","doi":"10.1029/2024JA033504","DOIUrl":"https://doi.org/10.1029/2024JA033504","url":null,"abstract":"<p>Following the largest magnetic storm in 20 years (10 May 2024), REPTile-2 on NASA's CIRBE satellite identified two new radiation belts containing 1.3–5 MeV electrons around <i>L</i> = 2.5–3.5 and 6.8–20 MeV protons around <i>L</i> = 2. The region around <i>L</i> = 2.5–3.5 is usually devoid of relativistic electrons due to wave-particle interactions that scatter them into the atmosphere. However, these 1.3–5 MeV electrons in this new belt seemed unaffected until a magnetic storm on 28 June 2024, perturbed the region. The long-lasting nature of this new electron belt has physical implications for the dependence of electron wave-particle interactions on energy, plasma density, and magnetic field strength. The enhancement of protons around <i>L</i> = 2 exceeded an order of magnitude between 6.8 and 15 MeV forming a distinct new proton belt that appears even more stable. CIRBE, after a year of successful operation, malfunctioned 25 days before the super storm but returned to functionality 1 month after the storm, enabling these discoveries.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033504","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362750","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":"Enhancing Deep Learning Ionospheric Modeling With Solar Radiation and Flare Classes","authors":"Yang Lin,&nbsp;Hanxian Fang,&nbsp;Die Duan,&nbsp;Hongtao Huang,&nbsp;Chao Xiao,&nbsp;Ganming Ren,&nbsp;Chenhao Li,&nbsp;Chuyue Zhou","doi":"10.1029/2024JA033319","DOIUrl":"https://doi.org/10.1029/2024JA033319","url":null,"abstract":"<p>The ionosphere is pivotal for satellite navigation, radio communication, and the modeling of space weather. However, the accurate three-dimensional modeling of ionospheric features remains a challenge. Since solar activity introduces changes in space weather, we collected COSMIC radio occultation observations of 2010–2020 with a suite of indices related to solar and geomagnetic activities, especially including solar EUV and X-ray radiation fluxes, to develop a deep learning model for the global ionospheric electron density. This model, which is called the Solar Flare and Radiation Neural Network (SFRNN) and is based on Embedding, Long Short-Term Memory and fully connected layers, presented excellent performance in reconstructing ionospheric profiles. In this study, 28-min was found to be the best input solar radiation interval for SFRNN with annual RMSEs of 6.24 × 10⁴ to 1.56 × 10⁵ el/cm³. Significantly, during solar flare events, SFRNN had a lower reconstruction error than the former artificial neural network (ANN) model that only uses space weather indices. The most substantial improvement was observed under X-class flares, where SFRNN exhibited a 18.3% lower Root Mean Squared Error than ANN. To further validate the modeling accuracy, electron density profiles derived from Jicamarca incoherent scatter radar (ISR) were used. SFRNN successfully provided profiles with high consistency with the ISR observation in the ionospheric layers. Our modeling results demonstrate that refined solar activity parameters can effectively improve reconstruction performance.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362749","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":"Modeling the Magnetospheric 3D X-Ray Emission From SWCX Using a Cusp-Magnetosheath Emissivity Model","authors":"S. J. Wharton,&nbsp;J. A. Carter,&nbsp;S. Sembay,&nbsp;Y. Soobiah,&nbsp;S. Nitti,&nbsp;T. R. Sun","doi":"10.1029/2024JA033307","DOIUrl":"https://doi.org/10.1029/2024JA033307","url":null,"abstract":"<p>A major challenge in solar-terrestrial physics is to understand the large-scale dynamics of planetary magnetospheres, such as the motion of the Earth's magnetopause. Currently, a combination of in situ measurements and numerical modeling has been used to address this challenge, but no global imaging has been available. The discovery of soft X-rays by the solar wind charge exchange (SWCX) process offers an opportunity to image the emitted X-ray photons. The SMILE mission, due for launch in late 2025, will carry a wide field of view soft X-ray telescope designed to observe emission from the magnetosheath and cusps. As no emission is expected from within the magnetosphere, it is expected that the magnetopause boundary will be observable from changes in X-ray intensity across the boundary. Extracting the 3D magnetopause boundary from the 2D X-ray images is a challenging task and several methods have been developed to model it. One method is to create a 3D emissivity model and adjust its parameters to fit the 2D X-ray image. In this paper, we develop a Cusp and Magnetosheath Emissivity Model (CMEM) and compare its performance to a previous model that did not include the cusps. We find CMEM has an improved fit to emissivity simulations for a wide range of solar wind densities, but that a poor choice of initial parameters can generate unphysical fits in both models. We propose and verify a method to resolve this that uses the upstream solar wind density to constrain some of the initial parameters.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033307","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362588","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":"Simulation of ULF Wave Modulated Electron Precipitation During the 17 March 2015 Storm","authors":"Maulik Patel,&nbsp;Mary Hudson,&nbsp;Brian Kress,&nbsp;Murong Qin","doi":"10.1029/2024JA033115","DOIUrl":"https://doi.org/10.1029/2024JA033115","url":null,"abstract":"<p>Ultra Low Frequency (ULF) waves play an important role in radiation belt dynamics, modulation of higher frequency wave modes and energetic particle precipitation. We investigate the effects of ULF waves on electron precipitation using a global magnetohydrodynamic (MHD) model and a test particle code. ULF waves are simulated using the Lyon-Fedder-Mobarry (LFM) global MHD model coupled to the Rice Convection Model with solar wind parameters provided as upstream boundary conditions. The MHD fields are used to trace electron trajectories as test particles in the Dartmouth rbelt3d model (Kress et al., 2007, https://doi.org/10.1029/2006JA012218). We simulate the 17 March 2015 storm, the largest geomagnetic storm of Solar Cycle 24 with a Dst of −223 nT, to examine electron precipitation associated with recurring ULF oscillations. The simulation results show that the initial bipolar electric field oscillation observed by Van Allen Probes causes energy dependent electron acceleration and inward radial transport, while the loss cone size increases on the dayside due to magnetopause compression causing precipitation loss across all energies. The subsequent ULF oscillations are more effective in producing precipitation for higher energy electrons that are drift phase bunched due to the initial electric field impulse, with loss continuing to occur on the dusk side where electrons drift in phase with anti-sunward propagating ULF waves.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362746","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":"Seasonal Variations in the Strength of Sporadic Meteor Sources Observed by Meteor Radar","authors":"Jiahui Luo,&nbsp;Yun Gong,&nbsp;Shaodong Zhang,&nbsp;Qihou Zhou,&nbsp;Zheng Ma","doi":"10.1029/2024JA033618","DOIUrl":"https://doi.org/10.1029/2024JA033618","url":null,"abstract":"<p>Sporadic meteors are a significant source of metals in the Earth's atmosphere and ionosphere, and the understanding of the seasonal variations of their strengths can provide valuable insights into the origins and orbits of cosmic dust particles near Earth. This study analyzes meteor echo data collected by an all-sky interferometric meteor radar in Ledong (LD, 18.4°N, 109.0°E) to quantify the strengths of sporadic meteor sources and their seasonal variations. The results indicate that the helion, antihelion, and apex sources are stronger than the north toroidal source, highlighting a concentration of sporadic meteors near the ecliptic plane and fewer near the ecliptic poles. Distinct seasonal variations are observed, with meteor activity peaking in April and September, likely corresponding to periods of increased meteor and dust particle density in Earth's orbit. Moreover, eight meteor showers are identified as significantly influencing the apparent radiant distributions and have comparable strengths with sporadic meteor sources. To enhance the analysis, a monthly radiant weighting system in ecliptic coordinates is developed, enabling precise calculation of source strengths and improved characterization of seasonal variations in radiant distributions. This research advances our understanding of sporadic meteors and their role in Earth's atmospheric processes, providing a foundation for future investigations into cosmic dust dynamics.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111826","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":"Piercing the Martian Veil: A Statistical Study of Interplanetary Magnetic Field Reach Through Ionospheric Pressure Balance","authors":"S. R. Shaver,&nbsp;L. Andersson,&nbsp;R. Ramstad,&nbsp;Bhagyashree Waghule,&nbsp;D. Brain,&nbsp;R. Lillis,&nbsp;T. Cravens,&nbsp;J. Halekas,&nbsp;S. Xu,&nbsp;P. C. Hinton,&nbsp;D. Malaspina,&nbsp;M. W. Liemohn,&nbsp;S. Ledvina,&nbsp;J. R. Gruesbeck,&nbsp;S. Curry","doi":"10.1029/2024JA033254","DOIUrl":"https://doi.org/10.1029/2024JA033254","url":null,"abstract":"<p>Mars, being a small planet with a tenuous atmosphere, does not have a sharp boundary between regions dominated by solar wind plasma and planetary plasma. Instead, this transition is typically extended, allowing the interplanetary magnetic field (IMF) to penetrate into the Martian ionosphere. However, the depth of this penetration is not well understood. Using 6 years of MAVEN data, we statistically assess locations where a transition exists between the dominance of magnetic versus cold (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>1 eV), thermal plasma pressure to better understand the reach of the IMF. We identify the presence or absence of pressure transitions from 200 to 800 km altitude for each MAVEN orbit and find a clear transition in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math> 55% of cases. The pressure transition locations are mapped in different coordinate systems that provide insight into the solar and planetary driving conditions that cause a detected transition region. Transitions are more likely to occur under weak-to-nominal solar wind conditions, away from strong crustal magnetic fields, near the terminator, on the dusk side of the planet compared to the dawn side, and in the negative solar wind motional electric field hemisphere. We speculate on possible causes for asymmetries that arise in the mapped locations of these pressure transitions and the effect that penetrated IMF may have on driving plasma dynamics in the Martian ionosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111828","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 Distribution of Pc1/EMIC Waves Relative to the Nightside Ionospheric Footprint of the Plasmapause","authors":"T. Bozóki,&nbsp;B. Heilig","doi":"10.1029/2024JA033385","DOIUrl":"https://doi.org/10.1029/2024JA033385","url":null,"abstract":"<p>Pc1 pulsations cover the 0.2–5 Hz frequency range with electromagnetic ion cyclotron (EMIC) waves of magnetospheric origin being generally accepted as their most important source. In the ionosphere, the initially transverse EMIC waves can couple to the compressional mode and propagate long distances in the ionospheric waveguide. By studying Pc1 waves in the topside ionosphere, we can obtain information on the spatial distribution of both the transverse (incident EMIC) and compressional waves. In the present paper, we make use of a new Swarm L2 product developed for characterizing Pc1 waves to explore the spatial distribution of these waves relative to the midlatitude ionospheric trough (MIT), which corresponds to the ionospheric footprint of the plasmapause (PP) at night. It is shown that the vast majority of Pc1 events are located inside the plasmasphere and that the spatial distributions clearly follow changes in the MIT/PP position at all levels of geomagnetic activity. In the topside ionosphere, the number of transverse Pc1 (incident EMIC) waves rapidly decreases outside the PP, while their occurrence peak is located considerably equatorward (|ΔMlat| = −5° to −15°) of the PP footprint, that is, inside the plasmasphere. On the other hand, the compressional Pc1 waves can propagate in the ionosphere outside the PP toward the poles, while in the equatorial direction there is a secondary maximum in their spatial distribution at low magnetic latitudes. Our results suggest that mode conversion taking place in the inductive ionosphere plays a crucial role in the formation of the presented spatial distributions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033385","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111829","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":"Investigation of the Fresnel Scale From Ionospheric Scintillation Spectra","authors":"K. Song,&nbsp;K. Meziane,&nbsp;A. M. Hamza,&nbsp;P. T. Jayachandran","doi":"10.1029/2024JA033239","DOIUrl":"https://doi.org/10.1029/2024JA033239","url":null,"abstract":"<p>Trans-ionospheric radio signals recorded on the ground exhibit random amplitude and phase fluctuations attributed to irregularities in the ionospheric electron density. Studying the ground-based measurements of trans-ionospheric radio signals can contribute to understanding plasma instability mechanisms leading to the development of ionospheric structures. In this regard, radio signals emitted from satellites, making up the Global Positioning System (GPS), and recorded by the Canadian High Arctic Ionospheric Network (CHAIN) GPS receivers, are analyzed to study the physical signatures of both amplitude and phase fluctuations. The current ionospheric scintillation paradigm posits that amplitude fluctuations arise from diffraction caused by Fresnel scale ionospheric structures, while refraction is responsible for signal phase variations. The amplitude power spectrum profile consistently displays a rollover frequency, which is not equal to the Fresnel frequency under the Taylor hypothesis. Phase screen theory is used to investigate this phenomenon further and identify an empirical relation between the rollover and Fresnel frequencies. Notably, we have found that the rollover frequency is consistently smaller than the Fresnel frequency. Furthermore, the Fresnel frequency extracted from two-component phase spectra tends to be larger than the rollover frequency. Based on our results, we have concluded that the identified Fresnel frequencies are directly linked to the ionospheric irregularities causing scintillation.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111827","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":"Venus' O 5577 Å Oxygen Green Line: A Global Diffuse Proton-Induced Aurora","authors":"Candace L. Gray,&nbsp;Kerstin Peter,&nbsp;Martin Pätzold,&nbsp;Silvia Tellmann,&nbsp;Tom Nordheim,&nbsp;Carl Schmidt,&nbsp;Nancy J. Chanover,&nbsp;Paul Withers","doi":"10.1029/2024JA032851","DOIUrl":"https://doi.org/10.1029/2024JA032851","url":null,"abstract":"<p>The Venusian O(¹S–¹D) 5577 Å “oxygen green line” has been an enigmatic feature of the Venusian atmosphere since its first attempted observation by the Venera spacecraft. Its first detection in 1999 and subsequent detections point to a unique auroral phenomena. However, the lack of (¹D–³P) 6300 Å “oxygen red line” emission suggests that the green line originates from deep in the ionosphere, much lower than current models predict. Here, we present 16 years of ground-based observations of the Venusian green line, comparing its behavior to the solar wind and spacecraft observations of the Venusian ionosphere. We find that all instances of green line emission occur during solar energetic particle (SEP) events, with a Matthews correlation coefficient of 0.93 between emission and the presence of SEPs. Coordinated observations between Venus Express and ground-based observatories show enhanced nightside ionospheric peak densities during the time of green line emission, with the lowest peak occurring at 115 km near local midnight. Such high density yet low altitude peaks suggest the presence of highly energetic particle precipitation. Initial modeling indicates <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≥</mo>\u0000 </mrow>\u0000 <annotation> ${ge} $</annotation>\u0000 </semantics></math>50 keV protons are needed to penetrate to such low altitudes. Comparisons of solar wind data confirm that such protons are present during all green line detections and nightside ionosphere enhancements. The association of SEP storms with green line emission and low nightside ionospheric peaks indicates that the green line is a unique global diffuse aurora, likely originating deep in the ionosphere and driven by proton precipitation, something that could be common for all non-magnetic planetary atmospheres.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032851","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111148","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}