Journal of Geophysical Research: Space Physics最新文献

{"title":"Effects of Fine Spectral Structure of Chorus Emissions on Nonlinear Scattering and Acceleration of Radiation Belt Electrons","authors":"Miroslav Hanzelka,&nbsp;Yuri Shprits,&nbsp;Dedong Wang,&nbsp;Bernhard Haas,&nbsp;Ondřej Santolík,&nbsp;Longzhi Gan","doi":"10.1029/2024JA033382","DOIUrl":"https://doi.org/10.1029/2024JA033382","url":null,"abstract":"<p>Whistler-mode chorus waves play a crucial role in accelerating electrons in Earth's outer radiation belt to relativistic and ultrarelativistic energies. While this electron evolution is typically modeled using a diffusion approximation for scattering, high-amplitude chorus waves induce nonlinear resonant effects that challenge this approach on short time scales. The long-term influence of these nonlinear interactions on radiation belt dynamics remains an unresolved issue. Recent simplified models suggest rapid nonlinear acceleration to ultrarelativistic energies, with formation of butterfly distributions during parallel wave propagation. In this study, we introduce a novel numerical approach based on Liouville phase space density mapping to investigate nonlinear scattering by high-amplitude waves over extended periods (minutes and beyond). We use a numerical wave field model of lower-band chorus risers that includes realistic fine-spectral features including subpacket modulations, phase decoherence, and jumps in wave normal angle. By incorporating these detailed spectral characteristics of the waves, we demonstrate that the rapid acceleration occurs across a broader pitch-angle range, forming a flat-top distribution. Similar effect is observed as the repetition period of chorus elements becomes shorter, with the additional effect of increased electron precipitation due to transition from bursty to continuous flux profiles in the loss cone. These findings highlight the importance of incorporating nonlinear effects and fine-scale wave properties in the future development of high-energy electron models for the outer radiation belt.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735529","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":"Limits on the Efficacy of Wave-Particle Interaction on the Energization and Transport of Atomic and Molecular Heavy Ionospheric Ions","authors":"Mei-Yun Lin,&nbsp;Raluca Ilie,&nbsp;Alex Glocer","doi":"10.1029/2024JA033523","DOIUrl":"https://doi.org/10.1029/2024JA033523","url":null,"abstract":"&lt;p&gt;Ionospheric molecular ions, such as &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, NO&lt;sup&gt;+&lt;/sup&gt;, and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, have been observed in Earth's high-altitude ionosphere and the magnetosphere by several spacecraft missions. Their presence not only indicates that they obtain sufficient energy through effective energization mechanisms, predominantly during the geomagnetically active times, but also provides clues regarding the connection between the ionosphere and the lower thermosphere. It is, however, unknown to date which physical processes are responsible for the transport and energization of molecular ions, as well as their relative contributions to the plasma surrounding the near-Earth region. In this study, we employ the Seven Ion Polar Wind Outflow Model (7iPWOM) and examine the properties of molecular &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, NO&lt;sup&gt;+&lt;/sup&gt;, and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{O}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; upflows and outflows in response to wave activity. The 7iPWOM is a hybrid polar wind model which solves the transport of e&lt;sup&gt;−&lt;/sup&gt;, H&lt;sup&gt;+&lt;/sup&gt;, He&lt;sup&gt;+&lt;/sup&gt;, N&lt;sup&gt;+&lt;/sup&gt;, O&lt;sup&gt;+&lt;/sup&gt;, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, NO&lt;sup&gt;+&lt;/sup&gt;, and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 ","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033523","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717119","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":"Generation of Perpendicular Ion Acoustic Waves in the Ramp Region of Earth's Bow Shock in the Presence of a Flat-Top Electron Velocity Distribution","authors":"Manpreet Singh,&nbsp;Federico Fraschetti,&nbsp;Joe Giacalone","doi":"10.1029/2025JA033745","DOIUrl":"https://doi.org/10.1029/2025JA033745","url":null,"abstract":"<p>We investigate the generation and stability of ion acoustic waves (IAWs) in the ramp region of perpendicular Earth's bow shock. Using a fluid model, we derive the dispersion relation of IAWs, assuming a flat-top electron velocity distribution function typically observed at interplanetary and Earth's bow shocks, along with jumps in plasma parameters. Our findings show that these electrostatic modes are non-dispersive within the shock ramp, which is in agreement with in-situ observations from the Magnetospheric Multiscale Mission (MMS). The calculated frequencies and phase velocities align closely with MMS measurements. Furthermore, we find that the growth rate of IAWs is more strongly affected by the ion temperature jump across the shock than by the electron temperature jump. The methodology developed in this work can be extended to investigate the generation and stability of other wave modes in diverse space and astrophysical plasma environments.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726758","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":"Loss Cone Offset Method for Evaluating the Effect of Magnetic Field Line Curvature Scattering (FLCS)","authors":"Ziming Wei,&nbsp;Yiqun Yu,&nbsp;Longxing Ma,&nbsp;Jinbin Cao","doi":"10.1029/2024JA033422","DOIUrl":"https://doi.org/10.1029/2024JA033422","url":null,"abstract":"<p>Magnetic Field Line Curvature Scattering (FLCS) is one of the important loss mechanism for energetic particles, referring to the scattering phenomenon where charged particles experience changes in their pitch angles due to the curvature and non-uniformity of magnetic field. Previous methods evaluating FLCS were suitable for less stretched configurations like dipole magnetic fields, but under Ts05 model, they led to non-physical results, especially in regions where the adiabatic parameter <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ε</mi>\u0000 </mrow>\u0000 <annotation> $varepsilon $</annotation>\u0000 </semantics></math> exceeds 0.584. To address this, we developed a new method for evaluating FLCS, named the Loss Cone Offset method (LCOM). The method first anchors the offset of loss cone center due to Borovsky et al. (2022), https://doi.org/10.1029/2021ja030106 and works by constructing the pitch angle offset after one FLCS as a function of initial pitch angle and gyro-phase angle, and then correcting the function by parameters fitting using test-particle-tracing results. Our calculations can effectively evaluate particle scattering due to FLCS in the range of 0°–90° pitch angles and adiabatic parameter <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ε</mi>\u0000 </mrow>\u0000 <annotation> $varepsilon $</annotation>\u0000 </semantics></math> ranging from 0.1 to 0.96. Loss Cone Offset method has good compatibility with previous methods under dipole magnetic field or TS05 magnetic field with low adiabatic parameters. It can effectively avoid non-physical results under stretched magnetic field and high adiabatic parameters, and evaluate the FLCS influence. Comparison with theoretical calculations, empirical formulas, and test-particle results demonstrates that the LCOM serves as an easy-to-use and reliable model for predicting particle loss due to FLCS in the magnetospheric dynamics. Its application deepens understanding of FLCS mechanisms, providing robust methodological support for developing physical models.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689613","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":"Resonant Infrasonic Disturbances in Total-Electron-Content During a Severe Thunderstorm on 23 October 2021","authors":"R. H. Honda,&nbsp;E. A. Kherani,&nbsp;C. A. O. B. Figueiredo,&nbsp;E. Astafyeva,&nbsp;C. M. Wrasse,&nbsp;K. P. Naccarato","doi":"10.1029/2024JA033679","DOIUrl":"https://doi.org/10.1029/2024JA033679","url":null,"abstract":"<p>Deep convective clouds and lightning activity during thunderstorms imprint Infrasonic (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>3 mili Hertz) oscillations in the ionospheric density or Traveling Ionospheric Disturbances (TIDs). The wave characteristics of these oscillations and the coupling mechanisms remain a subject of investigation, noting that the coupling energetics may alter the spectral and propagation characteristics. Moreover, the availability of numerous convective dynamics time scales makes the oscillation detection time uncertain. To study these aspects, the present work examines the spatial-temporal lightning flash rate during a severe thunderstorm (cloud top temperature <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>−80°C) from the GOES16 infrared channel and the total electron content of the ionosphere from the GNSS network over the tropical Southern Hemisphere. The study finds TIDs amplification above the deep convective clouds. The strongest amplification occurs at the earliest, at 9 min, from the most intense lightning flash rate and propagates at the most probable speed of 400–1,100 m/s. In contrast to the spectral peak of the active storm, which is 1.2 mHz, the spectral peak of TIDs is 4.8 mHz. The results highlight the magnitude of coupling energetics to determine the wave propagation characteristics of infrasonic TIDs.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033679","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689669","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":"Broadband Receiver for VLF On-Orbit Wave-Particle Interaction Experiments","authors":"I. R. Linscott,&nbsp;U. S. Inan,&nbsp;D. S. Lauben,&nbsp;W. M. Farrell,&nbsp;J. Payne,&nbsp;B. Mossiwir,&nbsp;C. Wang,&nbsp;K. Lee,&nbsp;W. R. Johnston,&nbsp;M. J. Starks,&nbsp;J. P. McCollough,&nbsp;J. C. Sanchez,&nbsp;Y.-J. Su","doi":"10.1029/2022JA030927","DOIUrl":"https://doi.org/10.1029/2022JA030927","url":null,"abstract":"<p>A broadband, multi-channel Very Low Frequency (VLF) radio receiver (BBR), developed as a sensitive analog, vector wave receiver for whistler-mode signals in the VLF range, was successfully flown on the Air Force Demonstration Science Experiment (DSX) Mission to Mid-Earth Orbit (Johnston et al., 2023, https://doi.org/10.1029/2022JA030771). The BBR is a radiation resistant, 5 × 2 channel receiver, integrated into the Wave Induced Precipitation of Electron Radiation (WIPER) instrument package on DSX. The BBR accepts electric wave signal inputs from (a) an 81.6 m tip-to-tip dipole VLF antenna on the DSX Y-boom, (b) a 16.3 m tip-to-tip dipole antenna on the DSX Z-boom, and (c) signals from a Tri-Axial Search Coil (TASC), an three-orthogonal axes magnetic wave search coil magnetometer mounted on the DSX + <i>Z</i> boom. The electric and magnetic VLF signals are processed in the BBR by two independent, radiation hardened five channel receivers: (a) a receiver of heritage design with commercial off-the-shelf components (COTS), and (b) a micro-receiver incorporating custom, radiation resistant, micro-electronics. The bandwidth of all five channels in both the heritage and micro designs covers from 10 Hz to 50 kHz. A software “receiver”, SRx, running in the on-board flight computer, the ECS, manages the BBR's data flow and data delivery to the ground. The SRx additionally computes supporting science data products such as Fourier transforms, multi-band filters and cross correlations among the BBR's electric and magnetic field channels to facilitate production of VLF wave normals.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2022JA030927","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689668","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":"Using VERB-4D to Model Ring Current Ions and Their Sensitivity to Plasmasphere Density","authors":"J. Himmelsbach,&nbsp;Y. Y. Shprits,&nbsp;H. Allison,&nbsp;B. Haas,&nbsp;M. Wutzig,&nbsp;M. Szabo-Roberts,&nbsp;D. Wang,&nbsp;A. Y. Drozdov","doi":"10.1029/2024JA033128","DOIUrl":"https://doi.org/10.1029/2024JA033128","url":null,"abstract":"<p>We extend the Versatile Electron Radiation Belt (VERB) code to model ring current ions. We validate our simulation results against observations from the Van Allen Probes mission for the St. Patrick's Day storm in 2013. We study the sensitivity to plasma density of the modeled losses from Coulomb collisions. To this end, we compare the Coulomb energy deposition rate, and trapped particle fluxes from simulations coupled to different models of plasmaspheric density: an empirical, a physics-based, and a machine learning model. The results show that cold plasma density plays an important role in the spatial distribution of Coulomb heating. Therefore, an accurate description of plasmasphere density is vital for modeling magnetosphere-ionosphere coupling. The impact of cold plasma density on the modeled ring current ion fluxes remains small.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689927","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":"Ionospheric Disturbances Detection Based on BDS-GEO Observations With Prophet Model Over China: A Case Study of May 2017 Geomagnetic Storm","authors":"Jintao Wang,&nbsp;Jun Tang,&nbsp;Chaoqian Xu,&nbsp;Liang Zhang,&nbsp;Youkun Wang","doi":"10.1029/2024JA033472","DOIUrl":"https://doi.org/10.1029/2024JA033472","url":null,"abstract":"<p>We investigate ionospheric disturbances over China during the May 2017 geomagnetic storm using an integrated data set, including total electron content (TEC) measurements from BeiDou Navigation Satellite System's (BDS) Geostationary Earth Orbit (GEO) observations, ionosonde data, Swarm satellites, and global navigation satellite system (GNSS) radio occultation (RO) data. TEC anomalies were identified using the Prophet forecasting model, and results were compared with three sliding time window methods, showing consistent outcomes. The significant TEC increase during the storm's main phase was driven by prompt penetration electric fields (PPEF) linked to interplanetary magnetic field (IMF) Bz fluctuations. During the recovery phase, TEC increased on May 29 night, associated with southward IMF Bz turning and westward PPEF. Notably, the TEC negative storm observed at the KUN1 station on the morning of May 29 was likely caused by F-layer uplift driven by the eastward overshielding electric field (OPEF) during the recovery phase, which induced Rayleigh-Taylor instability and resulted in the formation of plasma bubbles. Additionally, the electron density (Ne) measured by COSMIC and Swarm satellites, along with ionospheric F2 layer parameters critical frequency (foF2) and peak height (hmF2) showed significant increases during the storm. A negative ionospheric response was observed over China on May 30 from 00:00 to 12:00 UT, likely caused by thermosphere composition changes. This study highlights the efficiency of BDS-GEO satellites in monitoring ionospheric TEC variations, capturing spatiotemporal characteristics of disturbances, and validating the Prophet model for detecting anomalous TEC fluctuations during geomagnetic storms.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689926","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":"Statistical Characteristics of Nighttime ULF Waves Observed on the Surface of Mars by InSight","authors":"K. Webster,&nbsp;Y. Ma,&nbsp;S. Joy,&nbsp;P. J. Chi","doi":"10.1029/2024JA033292","DOIUrl":"https://doi.org/10.1029/2024JA033292","url":null,"abstract":"<p>Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) Fluxgate Magnetometer returned data from the Martian surface throughout the course of the InSight mission, between November 2018 and May 2022. Ultra-low frequency (ULF) electromagnetic waves are commonly observed by InSight during nighttime hours. We present a collection of 444 nighttime ULF wave events with characteristic frequencies ranging from 1 to 16 mHz (periods from about 1 to 17 min), with a median frequency of about 7 mHz (period of about 140 s). Ultra-low frequency wave activity is found across all nighttime hours, but the activity is more commonly observed after midnight local time. A subset of 104 InSight ULF wave events occur while Mars Atmosphere and Volatile EvolutioN (MAVEN) is located in the solar wind. During these events, the interplanetary magnetic field (IMF) deviates from its nominally expected orientation. We suggest that ULF waves are likely produced in the Martian magnetosphere by at least two different mechanisms and that the occurrence of the ULF waves on the surface is sensitive to the solar wind interaction with the Martian crustal fields. Further measurements by lander or orbiter missions will provide more information about the origin of ULF waves, how they reach the surface during the nighttime, and whether or not ULF waves can be used to perform magnetic sounding to study the subsurface of Mars.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033292","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689214","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":"MESSENGER Observations of a Possible Alfvén Wing at Mercury Driven by a Low Alfvénic Mach Number Interplanetary Coronal Mass Ejection","authors":"Charles F. Bowers,&nbsp;Caitríona M. Jackman,&nbsp;Xianzhe Jia,&nbsp;James A. Slavin,&nbsp;Joachim Saur,&nbsp;Mika K. G. Holmberg,&nbsp;Ryan M. Dewey,&nbsp;Daniel Heyner,&nbsp;Filip Elekes,&nbsp;Lina Z. Hadid,&nbsp;Benoit Lavraud,&nbsp;Yang Wang,&nbsp;Hans L. F. Huybrighs,&nbsp;Matthew J. Rutala,&nbsp;Alexandra R. Fogg,&nbsp;Stephenie Brophy Lee,&nbsp;Daragh M. Hollman","doi":"10.1029/2024JA033619","DOIUrl":"https://doi.org/10.1029/2024JA033619","url":null,"abstract":"&lt;p&gt;We investigate Mercury's response to rare, low Alfvénic Mach number &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({M}_{A}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; solar wind conditions using observations from the Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) mission. This study provides compelling evidence of Mercury's altered magnetospheric state under these extreme conditions, including the first observational confirmation of Alfvén wing formation at the planet. Our analysis estimates that the upstream conditions during the interplanetary coronal mass ejection (ICME) were sub-to trans-Alfvénic (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mo&gt;≤&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${M}_{A} le $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 1.5). These unusually low &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${M}_{A}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; solar wind conditions were driven by large interplanetary magnetic fields (IMF) associated with an ICME impact observed by MESSENGER on 30 December 2011. During this &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;17 hr event, MESSENGER completed one orbital pass through Mercury's magnetosphere, capturing magnetic field and plasma observations of its altered state. We compare these observations to a three-dimensional magnetohydrodynamic simulation of the event and to MESSENGER observations under typical &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${M}_{A}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; conditions (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mo&gt;≈&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033619","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689538","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}