The Lunar Environment heliospheric X-ray Imager (LEXI) is a wide field-of-view soft X-ray telescope developed to study solar wind-magnetosphere coupling. LEXI is part of the Blue Ghost 1 mission comprised of 10 payloads to be deployed on the lunar surface. LEXI monitors the dayside magnetopause position and shape as a function of time by observing soft X-rays (0.1–2 keV) emitted from solar wind charge-exchange between exospheric neutrals and high charge-state solar wind plasma in the dayside magnetosheath. Measurements of the shape and position of the magnetopause are used to test temporal models of meso- and macro-scale magnetic reconnection. To image the boundary, LEXI employs lobster-eye optics to focus X-rays to a microchannel plate detector with a 9.1 ^∘× 9.1^∘ field of view.

The Lunar Environment heliospheric X-ray Imager（LEXI） and Solar wind Magnetosphere Ionosphere Link Explorer（SMILE）missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective launches in the near future,to specify glo bal magnetic reconnection modes for varying solar wind conditions.To suppo rt the success of these scientific missions,it is critical to develop techniques that extract the magnetopause locations from the observed soft X-ray images.In this research,we introduce a new geometric equation that calculates the subsolar magnetopause position（R S ） from a satellite position,the look direction of the instrument,and the angle at which the X-ray emission is maximized.Two assumptions are used in this method:（1） The look direction where soft X-ray emissions are maximized lies tangent to the magnetopause,and（2） the magnetopause surface near the subsolar point is almost spherical and thus R S is nea rly equal to the radius of the magneto pause curvature.We create synthetic soft X-ray images by using the Open Geospace General Circulation Model（OpenGGCM） global magnetohydrodynamic model,the galactic background,the instrument point spread function,and Poisson noise.We then apply the fast Fourier transform and Gaussian low-pass filte rs to the synthetic images to re move noise and obtain accurate look angles for the soft X-ray pea ks.From the filte red images,we calculate R S and its accuracy for different LEXI locations,look directions,and solar wind densities by using the OpenGGCM subsolar magnetopause location as ground truth.Our method estimates R S with an accuracy of ＜0.3 RE when the solar wind density exceeds＞10 cm -3 .The accuracy improves for greater solar wind densities and during southward interplanetary magnetic fields.The method ca ptures the magnetopause motion during southwa rd interplaneta ry magnetic field turnings.Consequently,the technique will enable quantitative analysis of the magnetopause motion and help reveal the dayside reconnection modes for dynamic solar wind conditions.This technique will suppo rt the LEXI and SMILE missions in achieving their scientific o bjectives.

Research Article| December 01, 2023 The Dust, Atmosphere, and Plasma at the Moon William M. Farrell; William M. Farrell NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Search for other works by this author on: GSW Google Scholar Jasper S. Halekas; Jasper S. Halekas Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242 USA Search for other works by this author on: GSW Google Scholar Mihaly Horányi; Mihaly Horányi Department of Physics,University of Colorado, Boulder, CO 80309, USA Search for other works by this author on: GSW Google Scholar Rosemary M. Killen; Rosemary M. Killen NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Search for other works by this author on: GSW Google Scholar Cesare Grava; Cesare Grava Southwest Research Institute, 6220 Culebra Road, San Antonio, TX, 78238, USA Search for other works by this author on: GSW Google Scholar Jamey R. Szalay; Jamey R. Szalay Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ, 08544, USA Search for other works by this author on: GSW Google Scholar Mehdi Benna; Mehdi Benna NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Search for other works by this author on: GSW Google Scholar Pamela E. Clark; Pamela E. Clark Department of Physics, Earth Science and Space Science Engineering, Morehead State University, 123 Lappin Hall, Morehead, KY, 40351, USA Search for other works by this author on: GSW Google Scholar Michael R. Collier; Michael R. Collier NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Search for other works by this author on: GSW Google Scholar Anthony Colaprete; Anthony Colaprete NASA Ames Research Center, Space Science Division, Moffett Field, Mountain View, CA 94035, USA Search for other works by this author on: GSW Google Scholar Jan Deca; Jan Deca Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA Search for other works by this author on: GSW Google Scholar Richard C. Elphic; Richard C. Elphic NASA Ames Research Center, Space Science Division, Moffett Field, Mountain View, CA 94035, USA Search for other works by this author on: GSW Google Scholar Shahab Fatemi; Shahab Fatemi Department of Physics, Fysikhuset, plan 4, Linnaeus väg 24, FA419, Umeå Universitet, 901 87 Umeå, Sweden Search for other works by this author on: GSW Google Scholar Yoshifumi Futaana; Yoshifumi Futaana Swedish Institute of Space Physics, Bengt Hultqvists väg 1, 981 92 Kiruna, Sweden Search for other works by this author on: GSW Google Scholar Mats Holmström; Mats Holmström Swedish Institute of Space Physics, Bengt Hultqvists väg 1, 981 92 Kiruna, Sweden Search for other works by this author on: GSW Google Scholar Dana M. Hurley; Dana M. Hurley Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, 20723, USA Search for other works by this author on: GSW Google Scholar Georgiana Y. Kramer; Georgiana Y. Kramer Planetary Science Institute, Tucson, AZ, 85719, USA Search for other works by this author on: GSW Google Scholar Paul R. Mahaffy; Paul R. Mahaffy NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Search for other works by this author on: GSW Google Scholar Masaki N. Nishino; Masaki N. Nishino Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Yoshinodai 3-1-1, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan Search for other works by this author on: GSW Google Scholar Sarah K. Noble; Sarah K. Noble Mary W. Jackson NASA Headquarters, 300 Hidden Figures Way SW., Washington, DC, 20546, USA Search for other works by this author on: GSW Google Scholar Yoshifumi Saito; Yoshifumi Saito Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Yoshinodai 3-1-1, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan Search for other works by this author on: GSW Google Scholar Andrew R. Poppe; Andrew R. Poppe Space Sciences Laboratory, University of California, Berkeley, CA, 94720, USA Search for other works by this author on: GSW Google Scholar Kurt D. Retherford; Kurt D. Retherford Southwest Research Institute, 6220 Culebra Road, San Antonio, TX, 78238, USA Search for other works by this author on: GSW Google Scholar Xu Wang; Xu Wang Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA Search for other works by this author on: GSW Google Scholar Shoichiro Yokota Shoichiro Yokota Osaka University, Machikaneyama-cho, Toyonaka 560-0043, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information William M. Farrell NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Jasper S. Halekas Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242 USA Mihaly Horányi Department of Physics,University of Colorado, Boulder, CO 80309, USA Rosemary M. Killen NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Cesare Grava Southwest Research Institute, 6220 Culebra Road, San Antonio, TX, 78238, USA Jamey R. Szalay Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ, 08544, USA Mehdi Benna NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Pamela E. Clark Department of Physics, Earth Science and Space Science Engineering, Morehead State University, 123 Lappin Hall, Morehead, KY, 40351, USA Michael R. Collier NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Anthony Colaprete NASA Ames Research Center, Space Science Division, Moffett Field, Mountain View, CA 94035, USA Jan Deca Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA Richard C. Elphic NASA Ames Research Center, Space Science Division, Moffett Field, Mountain View, CA 94035, USA Shahab Fatemi Department of Physics, Fysikhuset, plan 4, Linnaeus väg 24, FA419, Umeå Universitet, 901 87 Umeå, Sweden Yoshifumi Futaana Swedish Institute of Space Physics, Bengt Hultqvists väg 1, 981 92 Kiruna, Sweden Mats Holmström Swedish Institute of Space Physics, Bengt Hultqvists väg 1, 981 92 Kiruna, Sweden Dana M. Hurley Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, 20723, USA Georgiana Y. Kramer Planetary Science Institute, Tucson, AZ, 85719, USA Paul R. Mahaffy NASA Goddard Space Flight Center 8800, Greenbelt Road, Greenbelt, MD, 20771 USA Masaki N. Nishino Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Yoshinodai 3-1-1, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan Sarah K. Noble Mary W. Jackson NASA Headquarters, 300 Hidden Figures Way SW., Washington, DC, 20546, USA Yoshifumi Saito Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Yoshinodai 3-1-1, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan Andrew R. Poppe Space Sciences Laboratory, University of California, Berkeley, CA, 94720, USA Kurt D. Retherford Southwest Research Institute, 6220 Culebra Road, San Antonio, TX, 78238, USA Xu Wang Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA Shoichiro Yokota Osaka University, Machikaneyama-cho, Toyonaka 560-0043, Japan Publisher: Mineralogical Society of America First Online: 04 Dec 2023 Copyright © 2023 by the Mineralogical Society of AmericaMineralogical Society of America Reviews in Mineralogy and Geochemistry (2023) 89 (1): 563–609. https://doi.org/10.2138/rmg.2023.89.13 Article history First Online: 04 Dec 2023 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation William M. Farrell, Jasper S. Halekas, Mihaly Horányi, Rosemary M. Killen, Cesare Grava, Jamey R. Szalay, Mehdi Benna, Pamela E. Clark, Michael R. Collier, Anthony Colaprete, Jan Deca, Richard C. Elphic, Shahab Fatemi, Yoshifumi Futaana, Mats Holmström, Dana M. Hurley, Georgiana Y. Kramer, Paul R. Mahaffy, Masaki N. Nishino, Sarah K. Noble, Yoshifumi Saito, Andrew R. Poppe, Kurt D. Retherford, Xu Wang, Shoichiro Yokota; The Dust, Atmosphere, and Plasma at the Moon. Reviews in Mineralogy and Geochemistry 2023;; 89 (1): 563–609. doi: https://doi.org/10.2138/rmg.2023.89.13 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search The topics of lofted dust, ejected atomic and molecular species, and plasma interactions at the Moon have made revolutionary strides since the last 'New Views of the Moon' review in 2006 (Jolliff et al. 2006). Specifically, in the last 13 years, there have been over a half-dozen spacecraft that are dedicated, wholly or in part, to the study of this neutral, ionized, and particulate atmosphere at the Moon. A key finding is that all three of these phenomena are inter-connected, and suggest the term 'exosphere' can be extended to particulates and surface-emitted plasma like reflected protons and exo-ions... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Aims. Solar Orbiter launched in February 2020 with the goal of revealing the connections between the Sun’s interior, atmosphere, and the heliosphere. The Solar Orbiter Heavy Ion Sensor (HIS) is a time-of-flight ion mass spectrometer dedicated to measuring heavy ions in the solar wind. Methods. We present an overview of the first measurements of heavy ion composition from HIS, reviewing the methods used to transform the spectra obtained on board into scientific data products and examining two solar wind case studies as well as the statistical properties of the heavy ion composition observed by HIS. We also carried out a comparison with prior measurements of heavy ions at L1. Results. The HIS data set provides the first mass- and charge-resolved heavy ion measurements in the inner heliosphere. Conclusions. These high temporal resolution data have the potential to transform our understanding of the connections between the solar wind and its origin at the Sun, as well as the interaction between the solar wind and the environment around planets, comets, and in the interstellar medium.

The VISualizing Ion Outflow via Neutral atom imaging during a Substorm (VISIONS) sounding rocket mission investigated the factors leading to ion outflow following a geomagnetic substorm. In situ and remote sensing instrumentation provided complementary measurements that have been combined to yield an in-depth look at the phenomena associated with ion outflow. In particular, the inclusion of instrumentation that provided high spatial and temporal resolution “images” of low-energy neutral atom (ENA) emissions from the nightside auroral zone following a substorm has led to new insights. The observed ENAs were spatially structured, and strongly associated with regions of intense 630.0 nm auroral emissions. The ENAs in the auroral zone were predominantly up-going, consistent with thick-target scattering in the region where the ENA mean free path is close to or less than the atmospheric scale height.

On October/November 2021 the Heavy Ion Sensor onboard Solar Orbiter observed data connected to three interplanetary shock events: Oct 30, Nov 3 and Nov 27. During all three events, the flux of suprathermal particles, defined as those having an energy larger than twice the energy of the solar wind component, showed remarkable intensification. We discuss those changes and specifically how particles of different mass/charge and energy/charge distribution before the shock are affected differently by the interaction with the shock front itself. From these three expampes, it appears that intensifications are stronger for species already having a seed population in the suprathermal regime.

Global magnetohydrodynamic models predict that plasma velocities vary almost linearly from 0 km s −1 at the nose of the stationary magnetopause on the stagnation streamline to a limiting value of 0.25 V SW for high solar wind Alfvénic Mach numbers at the nose of the bow shock, where V SW is the solar wind velocity. This paper presents a proof‐of‐concept study showing how two‐point measurements of the plasma velocity in the subsolar magnetosheath can be used to determine gradients in the plasma velocity and consequently the steady‐state or slowly moving locations of both the nose of the magnetopause and the nose of the bow shock. The results may be of use to those binning magnetosheath observations to develop empirical models, those testing models for magnetopause erosion or deposition in response to magnetic reconnection, and those determining the stand‐off distance of the bow shock as a function of solar wind conditions.

The Cusp Plasma Imaging Detector (CuPID) CubeSat observatory is a 6U CubeSat designed to observe solar wind charge exchange in magnetospheric cusps to test competing theories of magnetic reconnection at the Earth's magnetopause. The CuPID is equipped with three instruments, namely, a wide field-of-view (4.6° × 4.6°) soft x-ray telescope, a micro-dosimeter suite, and an engineering magnetometer optimized for the science operation. The instrument suite has been tested and calibrated in relevant environments, demonstrating successful design. The testing and calibration of these instruments produced metrics and coefficients that will be used to create the CuPID mission's data product.

How does solar wind energy flow through the Earth's magnetosphere, how is it converted and distributed? is the question we want to address. We need to understand how geomagnetic storms and substorms start and grow, not just as a matter of scientific curiosity, but to address a clear and pressing practical problem: space weather, which can influence the performance and reliability of our technological systems, in space and on the ground, and can endanger human life and health. Much knowledge has already been acquired over the past decades, particularly by making use of multiple spacecraft measuring conditions in situ, but the infant stage of space weather forecasting demonstrates that we still have a vast amount of learning to do. A novel global approach is now being taken by a number of space imaging missions which are under development and the first tantalising results of their exploration will be available in the next decade. In this White Paper, submitted to ESA in response to the Voyage 2050 Call, we propose the next step in the quest for a complete understanding of how the Sun controls the Earth's plasma environment: a tomographic imaging approach comprising two spacecraft in highly inclined polar orbits, enabling global imaging of magnetopause and cusps in soft X-rays, of auroral regions in FUV, of plasmasphere and ring current in EUV and ENA (Energetic Neutral Atoms), alongside in situ measurements. Such a mission, encompassing the variety of physical processes determining the conditions of geospace, will be crucial on the way to achieving scientific closure on the question of solar-terrestrial interactions.

The LEXI and SMILE missions will provide soft X-ray images of the Earth's magnetosheath and cusps after their anticipated launch in 2023 and 2024, respectively. The IBEX mission showed the potential of an Energetic Neutral Atom (ENA) instrument to image dayside magnetosheath and cusps, albeit over the long hours required to raster an image with a single pixel imager. Thus, it is timely to discuss the two imaging techniques and relevant science topics. We simulate soft X-ray and low-ENA images that might be observed by a virtual spacecraft during two interesting solar wind scenarios: a southward turning of the interplanetary magnetic field and a sudden enhancement of the solar wind dynamic pressure. We employ the OpenGGCM global magnetohydrodynamics model and a simple exospheric neutral density model for these calculations. Both the magnetosheath and the cusps generate strong soft X-rays and ENA signals that can be used to extract the locations and motions of the bow shock and magnetopause. Magnetopause erosion corresponds closely to the enhancement of dayside reconnection rate obtained from the OpenGGCM model, indicating that images can be used to understand global-scale magnetopause reconnection. When dayside imagers are installed with high-ENA inner-magnetosphere and FUV/UV aurora imagers, we can trace the solar wind energy flow from the bow shock to the magnetosphere and then to the ionosphere in a self-standing manner without relying upon other observatories. Soft X-ray and/or ENA imagers can also unveil the dayside exosphere density structure and its response to space weather.

As the solar wind flows by the Moon, an antisunward-directed low-density wake forms as the plasma expands to fill in the trailing void in the plasma flow. Analytical modeling and modern plasma simulations suggest that plasma quasi-neutrality could possibly be broken close to the terminator obstruction as solar wind electrons expand into the wake ahead of the ions, leading to the formation of a standing (time-stationary) double layer. The objective of the Terminator Double Layer Explorer is to extend the fundamental understanding of the plasma expansion into the trailing near-vacuum wake region by (1) identifying any plasma expansion density anomalies at low altitudes near the terminator wake initiation region, (2) assessing the highly variable solar wind’s effect on the low-altitude wake region, and (3) determining if plasma neutrality is maintained or lost during passages through the low-altitude expansion region. The mission concept uses a propulsion-driven CubeSat with ion spectrometer and plasma wave system in elliptical orbit about the Moon with periselene near the terminator. Over the course of the mission, the periselene decreases, placing the CubeSat ever closer to the terminator wake initiation location and the possible nonneutral region.

The VISIONS‐2 35.039 sounding rocket was launched from Ny‐Ålesund, Svalbard, on 7 December 2018 at 11:06 UT, and traveled overhead of the cusp aurora. The payload reached an apogee of 806.6 km and provided measurements of the electric field (E) and electron density (Ne) with a high sampling rate of 6,250 Hz. The high‐sampling‐data make it possible to estimate the horizontal structure of E and Ne on scales ranging from meters to kilometers scale. The horizontal variation in the electron density and electric field (ΔNe/Ne and ΔE) and integrated power of Ne and E (ΣPNe and ΣPE) for 1–10, 10–100, and 100–1,000 Hz range were derived. The derived values were compared with the 557.7 and 630.0 nm emission intensities obtained from an all‐sky camera installed in Ny‐Ålesund projected at the footprint of the rocket, which was calculated by tracing the Earth's magnetic field line from the rocket altitude to the emission layer. ΔNe/Ne, ΔE, ΣPNe, and ΣPE increased with the 630.0 nm emission intensity. Of particular interest is the lower level irregularity was observed when the 557.7 nm emission intensity exceeded 4.5 kR compared with other time interval. This may suggest that particle impact ionization created sufficient Pedersen conductance in the E‐region to short the F‐region current. This short‐circuit seemed to cause the suppression of the irregularities in the F‐region and lower level irregularities were also observed in the rocket altitude.

In a seminal analysis, Fuselier et al. (2020) combined subsolar in situ magnetosheath plasma observations with remote energetic neutral atom (ENA) observations to derive an exospheric neutral density of 11 cm −3 in the vicinity of the subsolar magnetopause. This commentary extends the analysis of Fuselier et al. (2020) to (a) employ predicted and observed magnetosheath plasma parameters at times other than those immediately following an MMS magnetopause crossing, (b) take into account the component of the plasma bulk flow transverse to the ENA spacecraft's line‐of‐sight through the flank magnetosheath, and (c) consider the cooling that results from the antisunward expansion of the magnetosheath plasma. With these additional considerations, subsolar exospheric neutral densities rise by a factor of 4.1–4.5 to 45–50 cm −3 , consistent with results from previous studies.

The Solar Orbiter mission was launched in 2020 into an orbit that will explore the inner heliosphere. During its orbit, periods of quasi-corotation with the Sun will enable determination of the source regions on the Sun for solar wind structures. The Solar Wind Analyser (SWA) is a suite of instruments that provide in-situ measurements of solar wind electrons, protons, alpha particles, and heavy ions. The SWA-Heavy Ion Sensor (HIS) is optimized to measure heavy ions in the solar wind, pickup ions, and suprathermal ions in an energy range spanning from 0.5- 75keV/e. We present measurements of heavy ion composition from SWA-HIS taken during the cruise phase of the mission to highlight the capabilities of the instrument and the observations we expect to collect over the next 10 years. We discuss how SWA-HIS will enable linkages between the Sun and the solar wind to reveal the nature of the acceleration and release of the solar wind and the sources and structure of the solar wind. We will also provide an overview of the available data and accessibility of the public datasets.

Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Journal of Geophysical Research - Space Physics. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]The Tractrix Magnetopause: A Novel Physics-Based Functional Form for the Magnetopause ShapeAuthorsC. J.O'BrieniDMichael RCollieriDBrianWalshDavid GarySibeckiDE.TayloriDSee all authors C. J. O'BrieniDCorresponding Author• Submitting AuthorBoston UniversityiDhttps://orcid.org/0000-0002-2267-4140view email addressThe email was not providedcopy email addressMichael R CollieriDNASA Goddard SFCiDhttps://orcid.org/0000-0001-9658-6605view email addressThe email was not providedcopy email addressBrian WalshBoston Universityview email addressThe email was not providedcopy email addressDavid Gary SibeckiDGSFCiDhttps://orcid.org/0000-0003-3240-7510view email addressThe email was not providedcopy email addressE. TayloriDHoward UniversityiDhttps://orcid.org/0000-0002-6710-386Xview email addressThe email was not providedcopy email address