Space Science Reviews最新文献

{"title":"Magnetic Reconnection in Space: An Introduction.","authors":"J L Burch, Rumi Nakamura","doi":"10.1007/s11214-025-01145-x","DOIUrl":"10.1007/s11214-025-01145-x","url":null,"abstract":"<p><p>An International Space Science Institute (ISSI) workshop was convened to assess recent rapid advances in studies of magnetic reconnection made possible by the NASA Magnetospheric Multiscale (MMS) mission and to place them in context with concurrent advances in solar physics by the Parker Solar Probe, astrophysics, planetary science and laboratory plasma physics. The review papers resulting from this study focus primarily on results obtained by MMS, and these papers are complemented by reports of advances in magnetic reconnection physics in these other plasma environments. This paper introduces the topical collection \"Magnetic Reconnection: Explosive Energy Conversion in Space Plasmas\", in particular introducing the new capabilities of the MMS mission used in majority of the articles in the collection and briefly summarizing the advances obtained from MMS.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 1","pages":"19"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11821752/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143433831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SUDA: A SUrface Dust Analyser for Compositional Mapping of the Galilean Moon Europa.","authors":"Sascha Kempf, Scott Tucker, Nicolas Altobelli, Christelle Briois, Morgan L Cable, Eberhard Grün, Murthy S Gudipati, Bryana L Henderson, Hsian-Wen Hsu, Kevin Hand, Mihaly Horanyi, Frank Postberg, Jürgen Schmidt, Ralf Srama, Zoltan Sternovsky, Gabriel Tobie, Mikhail Y Zolotov, Chris Belting, Susan Bortfeldt, Jordy Bouwman, Nat Brennan, Karen Bryant, Timothy Cassidy, David Crotser, Alexandra Curtin, Elz DeVito, Donrich Ebuen, Nat Faber, Melanie Fisher, John Fontanese, Maxwell Fowle, Wendy Frank, Scott Gurst, Sally Haselschwardt, Vaughn Hoxie, Karl Hubbell, David James, Mark Kien, Scott Knappmiller, Rick Kohnert, Alexander Lampe, Mark Lankton, Sean Lev-Tov, Crystal McGinn, Marc Miller, Gregory Newcomb, Samuel Oberg, Leela O'Brien, Kathrine Pilewskie, Shawn Polson, Victoria Scarffe-Barrett, David Summers, Stacy Wade, Alexandria Ware, Alan Yehle, Corinne Wuerthner, Adrian Garcia Arteaga, Bogdan Oaida, Chad Eberl, Polly Fitton, William Goode, Zuni Levin, Gwyneth Lowry, Jared Stanley, Anthony Tracy, Zach Ulibarri, Ethan Williams, Camille Yoke, Ben S Southworth, Jonathan K Hillier, Nozair Khawaja, Fabian Klenner, Maryse Napoleoni, Jonas Simolka, Jason Sioeng","doi":"10.1007/s11214-025-01134-0","DOIUrl":"10.1007/s11214-025-01134-0","url":null,"abstract":"<p><p>The Surface Dust Analyser (SUDA) is a mass spectrometer onboard the Europa Clipper mission for investigating the surface composition of the Galilean moon Europa. Atmosphereless planetary moons such as the Galilean satellites are wrapped into a ballistic dust exosphere populated by tiny samples from the moon's surface produced by impacts of fast micrometeoroids. SUDA will measure the composition of such surface ejecta during close flybys of Europa to obtain key chemical signatures for revealing the satellite's composition such as organic molecules and salts, history, and geological evolution. Because of their ballistic orbits, detected ejecta can be traced back to the surface with a spatial resolution roughly equal to the instantaneous altitude of the spacecraft. SUDA is a Time-Of-Flight (TOF), reflectron-type impact mass spectrometer, optimized for a high mass resolution which only weakly depends on the impact location. The instrument will measure the mass, speed, charge, elemental, molecular, and isotopic composition of impacting grains. The instrument's small size of <math><mn>268</mn> <mspace></mspace> <mi>mm</mi> <mo>×</mo> <mn>250</mn> <mspace></mspace> <mi>mm</mi> <mo>×</mo> <mn>171</mn></math> <math><mspace></mspace> <mi>mm</mi></math> , radiation-hard design, and rather large sensitive area of 220 cm² matches well the challenging demands of the Clipper mission.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 1","pages":"10"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11836169/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143469311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Psyche Multispectral Imager Investigation: Characterizing the Geology, Topography, and Multispectral Properties of a Metal-Rich World.","authors":"J F Bell, M A Ravine, M A Caplinger, J A Schaffner, S M Brylow, M J Clark, D A Peckham, P T Otjens, G J Price, T Rowell, J W Ravine, J D Laramee, R C Juergens, W Morgan, A G Parker, D A Williams, A Winhold, S Dibb, E Cisneros, M Walworth, H Zigo, L Auchterlonie, N Warner, H Bates-Tarasewicz, N Amiri, C Polanskey, N Mastrodemos, R S Park, N K Alonge, R Jaumann, R P Binzel, T J McCoy, M G Martin, P A Arthur","doi":"10.1007/s11214-025-01169-3","DOIUrl":"10.1007/s11214-025-01169-3","url":null,"abstract":"<p><p>The Psyche Multispectral Imager (\"the Imager\") is a payload system designed to directly achieve or to indirectly enable the key scientific goals and optical navigation requirements of NASA's Psyche mission, which will conduct the first up-close orbital investigation of the metal-rich Main Belt asteroid (16) Psyche. The Imager consists of a pair of block redundant cameras and electronics that are mounted inside the thermally controlled spacecraft body, with a view out the spacecraft -X panel that will be nadir-pointed during nominal asteroid orbital mapping operations. The two identical Camera Heads are connected to a separate Digital Electronics Assembly (DEA) box that interfaces to the spacecraft avionics and that provides power, commanding, data processing, and onboard image storage. The Imager system shares significant heritage with imaging instruments flown on the <i>Mars Climate Orbiter</i>, the <i>Mars Science Laboratory</i> and <i>Mars 2020</i> rovers, and <i>Juno</i>. Each camera consists of a 1600 × 1200 photosensitive pixel charge-coupled device (CCD) detector and its associated electronics, a 9-position filter wheel assembly, a compact catadioptric <math><mi>f</mi></math> /2.9 telescope with a fixed focal length of 148 mm, and a sunshade to minimize stray and scattered light. The Imager CCD, filters, and optics enable broadband polychromatic (∼540 ± 250 nm) imaging plus narrowband imaging in 7 colors centered from 439 to 1015 nm. An additional neutral density filter enables protection of the CCD from direct solar illumination. Each camera has a field of view of 4.6° × 3.4° and an instantaneous field of view of 50 μrad/pixel that enables imaging of the asteroid at scales ranging from ∼35 m/pix from 700 km altitude to ∼4 m/pix at 75 km altitude. The primary camera (\"Imager A\") is pointed along the spacecraft -X axis, and the backup camera (\"Imager B\") is toed-out by 3.7° to potentially enable greater surface area coverage per unit time if both Imagers are operated simultaneously during some mission phases. Stereoscopic mapping is performed by observing the same surface regions with either camera over a range of off-nadir pointing angles.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 4","pages":"47"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12095399/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144143551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tidal Deformation and Dissipation Processes in Icy Worlds.","authors":"G Tobie, P Auclair-Desrotour, M Běhounková, M Kervazo, O Souček, K Kalousová","doi":"10.1007/s11214-025-01136-y","DOIUrl":"10.1007/s11214-025-01136-y","url":null,"abstract":"<p><p>Tidal interactions play a key role in the dynamics and evolution of icy worlds. The intense tectonic activity of Europa and the eruption activity on Enceladus are clear examples of the manifestation of tidal deformation and associated dissipation. While tidal heating has long been recognized as a major driver in the activity of these icy worlds, the mechanism controlling how tidal forces deform the different internal layers and produce heat by tidal friction still remains poorly constrained. As tidal forcing varies with orbital characteristics (distance to the central planet, eccentricity, obliquity), the contribution of tidal heating to the internal heat budget can strongly change over geological timescales. In some circumstances, the tidally-produced heat can result in internal melting and surface activity taking various forms. Even in the absence of significant heat production, tidal deformation can be used to probe the interior structure, the tidal response of icy moons being strongly sensitive to their hydrosphere structure. In the present paper, we review the methods to compute tidal deformation and dissipation in the different layers composing icy worlds. After summarizing the main principle of tidal deformation and the different rheological models used to model visco-elastic tidal response, we describe the dissipation processes expected in rock-dominated cores, subsurface oceans and icy shells and highlight the potential effects of tidal heating in terms of thermal evolution and activity. We finally anticipate how data collected by future missions to Jupiter's and Saturn's moons could be used to constrain their tidal response and the consequences for past and present activities.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 1","pages":"6"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11739232/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143011925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The TRACERS Analyzer for Cusp Electrons.","authors":"Jasper S Halekas, Christian Hansen, Suranga Ruhunusiri, David Sheets, Antonio Washington, Richard M Beals, Scott R Bounds, Andrew Carton, Ivar W Christopher, Danielle Crawford, Katherine Deasy, Jeffrey S Dolan, Richard Dvorsky, Connor Feltman, Garret Hinson, Samuel Hisel, Amanda Lasko, Aidan Moore, Katherine Morris, Chris W Piker, Kevin Steele, Darrelle Wilkinson, Craig A Kletzing, David M Miles","doi":"10.1007/s11214-025-01147-9","DOIUrl":"10.1007/s11214-025-01147-9","url":null,"abstract":"<p><p>The Analyzer for Cusp Electrons (ACE) instruments on the Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) mission provide measurements of electron velocity distribution functions from two closely spaced spacecraft in a low Earth orbit that passes through the magnetospheric cusp. The precipitating and upward-going electrons provide a sensitive probe of the magnetic field line topology and electrostatic potential structure, as well as revealing dynamic processes. ACE measurements contribute to the top-level TRACERS goals of characterizing the spatial and temporal variation of magnetic reconnection at the terrestrial magnetopause and its relationship to dynamic structures in the cusp. ACE utilizes a classic hemispheric electrostatic analyzer on a spinning platform to provide full angular coverage with 10 degree by 7 degree resolution. ACE can measure electrons over an energy range of 20-13,500 electron volts, with fractional energy resolution of 19%. ACE provides 50 ms cadence measurements of the electron velocity distribution, enabling sub-kilometer spatial resolution of cusp boundaries and other structures.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 1","pages":"21"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11828801/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143433835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Flight Performance of the MAGIC Magnetoresistive Magnetometer on the RadCube CubeSat.","authors":"J P Eastwood, P Brown, T Oddy, M O Archer, R Baughen, I Belo Ferreira, C Cobo Torres, E Cupido, H Eshbaugh, C Palla, A Vitkova, C L Waters, B Whiteside, B Zabori, A Hirn, D Nolbert, D Milánkovich, Z G Kovács, G Santin, R Walker","doi":"10.1007/s11214-025-01170-w","DOIUrl":"10.1007/s11214-025-01170-w","url":null,"abstract":"<p><p>In studying space physics, planetary science, and space weather, space-based in situ measurements of the magnetic field are fundamental to understanding underlying physical processes, as well as providing context for other observations. Whilst in many cases instrument design is not severely constrained by the available resource envelope, there are many applications, particularly when using new generations of spacecraft platforms such as CubeSats, that require very low resource sensors. In this context we review the design, development, construction, and flight of the highly miniaturised MAGIC (MAGnetometer from Imperial College) instrument on the RadCube Technology Demonstration CubeSat. MAGIC consists of a boom-mounted (outboard) Anisotropic Magneto-Resistive (AMR) vector sensor connected by harness to a single electronics card inside RadCube. A second inboard AMR vector sensor is mounted on the electronics card. RadCube launched on 17 August 2021 to a sun-synchronous low-Earth polar orbit, with the main mission lasting until April 2022. Routine operations were subsequently extended to the end of 2022, with further special operations in 2023 and 2024 before re-entry on 20 August 2024. Here we review RadCube observations made over more than two years in orbit. Key results from MAGIC on RadCube include meeting ESA space weather magnetic field measurement requirements with both the outboard and inboard sensor, as well as detection of field aligned current signatures at high latitude.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 4","pages":"45"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12078372/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144094814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SMILE Modeling Working Group: Modeling and Analysis of X-ray and Ultraviolet Images of Solar Wind - Earth Interactions.","authors":"Hyunju K Connor, Tianran Sun, Andrey Samsonov, Jun Liang, Andrew Read, Dalin Li, Gonzalo Cucho-Padin, Jaewoong Jung, Brenden Bickner, C Philippe Escoubet, Colin Forsyth, Steven Sembay, David Sibeck, Emma Spanswick, Dmytro Sydorenko, Chi Wang","doi":"10.1007/s11214-025-01172-8","DOIUrl":"10.1007/s11214-025-01172-8","url":null,"abstract":"<p><p>The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) is a joint European and Chinese spacecraft scheduled to launch in 2025 into a highly elliptical polar orbit. It will carry four instruments: the Soft X-ray Imager (SXI), the UltraViolet Imager (UVI), the Light Ion Analyzer (LIA), and the MAGnetometer (MAG). SMILE will image the dayside magnetosheath and cusps in soft X-ray, as well as the northern auroral oval in ultraviolet, for ∼41 continuous hours per orbit while simultaneously measuring plasma and magnetic field along its path. SMILE aims to advance our understanding of global solar wind - magnetosphere - ionosphere interactions. The Modeling Working Group (MWG), established in 2018, has fostered various modeling studies to ensure the successful scientific outcome of the SMILE mission. This paper overviews several MWG activities related to the SMILE SXI and UVI instruments. Firstly, we introduce the simulation of soft X-ray images of the Earth's dayside magnetosphere, the SMILE orbit, and the SXI target visibilities. Secondly, we discuss multiple techniques developed for soft X-ray image analysis and the SXI's capability to capture multi-scale interactions between the solar wind and Earth's magnetosphere. Thirdly, we focus on the role of exospheric hydrogen density in determining near-Earth soft X-ray emissions, introducing several studies that estimate the exospheric density near the subsolar magnetopause location and its variability during geomagnetic storms. Finally, we present the modeling efforts for simulating the UVI instrument performance and the kinetic transport of suprathermal electrons and their impact on UV emissions.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 4","pages":"46"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12092568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Outstanding Questions and Future Research on Magnetic Reconnection.","authors":"R Nakamura, J L Burch, J Birn, L-J Chen, D B Graham, F Guo, K-J Hwang, H Ji, Y V Khotyaintsev, Y-H Liu, M Oka, D Payne, M I Sitnov, M Swisdak, S Zenitani, J F Drake, S A Fuselier, K J Genestreti, D J Gershman, H Hasegawa, M Hoshino, C Norgren, M A Shay, J R Shuster, J E Stawarz","doi":"10.1007/s11214-025-01143-z","DOIUrl":"10.1007/s11214-025-01143-z","url":null,"abstract":"<p><p>This short article highlights unsolved problems of magnetic reconnection in collisionless plasma. Advanced in-situ plasma measurements and simulations have enabled scientists to gain a novel understanding of magnetic reconnection. Nevertheless, outstanding questions remain concerning the complex dynamics and structures in the diffusion region, cross-scale and regional couplings, the onset of magnetic reconnection, and the details of particle energization. We discuss future directions for magnetic reconnection research, including new observations, new simulations, and interdisciplinary approaches.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 1","pages":"17"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11814039/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143415323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Formation of Saturn's Regular Moons in the Context of Giant Planet Moons Formation Scenarios.","authors":"Michel Blanc, Aurélien Crida, Yuhito Shibaike, Sebastien Charnoz, Maryame El Moutamid, Paul Estrada, Olivier Mousis, Julien Salmon, Antoine Schneeberger, Pierre Vernazza","doi":"10.1007/s11214-025-01156-8","DOIUrl":"10.1007/s11214-025-01156-8","url":null,"abstract":"<p><p>This article explores the different formation scenarios of the Kronian moons system in the context of a highly dissipative Saturn, with the objective of identifying the most likely of these scenarios. First, we review the diversity of objects - moons and rings - orbiting solar system giant planets, and the diversity of their architectures, which formation scenarios must reproduce. We then identify in this broader context the specific features of the Saturn system, such as the particularly large spectrum of its moon masses, the uniqueness of Titan and the presence of both dense and tenuous rings, before discussing the applicability of the different giant planet moon formation scenarios to the Saturn case. We discuss each of the most relevant scenarios and their respective merits. Finally, we tentatively propose a \"favorite\" scenario and we identify the key observations to be made by future space missions and/or Earth-based telescopic observations to validate this scenario or possibly alternative ones.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 3","pages":"35"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11925992/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143693353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Analyzer for Cusp Ions (ACI) on the TRACERS Mission.","authors":"Stephen A Fuselier, Matthew A Freeman, Craig A Kletzing, Sean R Christopherson, Michael J Covello, Daniel De Luna, Raymond L Doty, Colin G Elder, Judith D Furman, Jonathan Gasser, Don E George, Roman G Gomez, Guy A Grubbs, Kristie Llera, David M Miles, Joey Mukherjee, Kristian B Persson, Steven M Petrinec, Dinesh K V Radhakrishnan, Christopher L Ramirez, Ashley S Reisig, Charline Rodriguez, Courtney A Rouse, David A Ruggles, Shawn D Schwarz, Jonathan R Sekula, Linda J Shipp, Justyna M Sokół, Kylie M Sullivan, Karlheinz J Trattner, Sarah K Vines","doi":"10.1007/s11214-025-01154-w","DOIUrl":"10.1007/s11214-025-01154-w","url":null,"abstract":"<p><p>The Analyzers for Cusp Ions (ACIs) on the TRACERS mission measure ion velocity distribution functions in the magnetospheric cusp from two closely spaced spacecraft in low Earth orbit. The precipitating and upflowing ion measurements contribute to the overarching goal of the TRACERS mission and are key to all three science objectives of the mission. ACI is a toroidal top-hat electrostatic analyzer on a spinning platform that provides full angular coverage with instantaneous 22.5° × ∼6° angular resolution for a single energy step. ACI has an ion energy range from ∼8 eV/e to 20,000 eV/e covered in 47 logarithmic-spaced energy steps with fractional energy resolution of ∼10%. It provides reasonably high cadence (312 ms) measurements of the ion energy-pitch angle distribution with good sensitivity and energy resolution, enabling detection of cusp boundaries and characterization of cusp ion steps.</p>","PeriodicalId":21902,"journal":{"name":"Space Science Reviews","volume":"221 2","pages":"30"},"PeriodicalIF":9.1,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11906535/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143650873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}