During the 21-22 January 2005 magnetic storm, the FAST satellite observed warm (< few keV) ions in discrete energy bands on the dayside at similar to 3,000 km altitude for more than 6.5 hr. We suggest that the ionospheric energy-banded ions represent the low-altitude edge of the warm plasma cloak observed simultaneously by magnetospheric satellites. This is a clear example of the multi-species ion energy bands (10 eV to several keV) observed during strong magnetic storms by the FAST satellite, stretching from the diffuse auroral region to the plasmapause with lifetimes up to 12 hr. The close association of these energy-banded ions with magnetic storms, their broad latitudinal extent, and the presence of multiple ion species in the same energy band, rather than at the same velocity, indicate that this is a distinct phenomenon from other types of energy-banded ions. During the 21-22 January 2005 magnetic storm, the dayside ion energy band structures, centered at 10 eV (H+), 40 eV (H+ and He+), and 160 eV (H+, He+, and O+), were consistent with a "time-of-flight and velocity filter" formation process acting on a near-cusp, impulsive outflow of a <200 eV multi-species ion-source population, poleward and in the same hemisphere as FAST. Understanding the sources and dynamics of warm energy-banded ions and their linkage to the warm plasma cloak is important because during superstorms these ions are transported to L values as low as L similar to 1.2 in the dawn sector, significantly altering the energetics of the mid-latitude ionosphere.

The Martian magnetotail current sheet exhibits a dawn-dusk asymmetry, but the reasons for this shift remain unclear. Although crustal magnetic fields influence this asymmetry, most magnetohydrodynamic (MHD) simulations focus on the subsolar orientation of 180 degrees W, 0 degrees N, which places the strongest crustal fields on the dayside and overlooks potential longitudinal variability. This study employs the BATS-R-US multispecies MHD code to simulate the solar wind interaction with Mars at various subsolar longitudes, aiming to evaluate how the orientation of crustal magnetic fields shapes the structure of the magnetotail. The results show that the crustal field orientation controls whether the current sheet shifts dawnward, duskward, or alternates between the two regions. Current density analysis reveals that the current sheet is bifurcated (two spatially distinct current channels) from 0 degrees W to 195 degrees W and uniform from 210 degrees W to 345 degrees W. Analysis of the mass flux shows that it aligns with the bifurcation/uniformity of the current density, showing where plasma escapes through the magnetotail. The study demonstrates that crustal field orientation is a key factor in shaping the Martian magnetotail structure.

The geospace plume, referring to the combined processes of the plasmaspheric and the ionospheric storm-enhanced density (SED)/total electron content (TEC) plumes, is one of the unique features of geomagnetic storms. The apparent spatial overlap and joint temporal evolution between the plasmaspheric plume and the equatorial mapping of the SED/TEC plume indicate strong magnetospheric-ionospheric coupling. However, a systematic modeling study of the factors contributing to geospace plume development has not yet been performed due to the lack of a sufficiently comprehensive model including all the relevant physical processes. In this paper, we present a numerical simulation of the geospace plume in the March 31, 2001 storm using the Multiscale Atmosphere Geospace Environment model. The simulation reproduces the observed linkage of the two plumes, which, we interpret as a result of both being driven by the electric field that maps between the magnetosphere and the ionosphere. The model predicts two velocity channels of sunward plasma drift at different latitudes in the dusk sector during the storm main phase, which are identified as the sub-auroral polarization streams (SAPS) and the convection return flow, respectively. The SAPS is responsible for the erosion of the plasmasphere plume and contributes to the ionospheric TEC depletion in the midlatitude trough region. We further find the spatial distributions of the magnetospheric ring current ions and electrons, determined by a delicate balance of the energy-dependent gradient/curvature drifts and the E´B drifts, are crucial to sustain the SAPS electric field that shapes the geospace plume throughout the storm main phase.

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 (< 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 similar to 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.

The Geospace Environment Modeling (GEM) program regularly issues “community challenges” in which researchers examine a particular space physics phenomenon or geomagnetic activity event, often running numerical models to assess dominant processes and understand the timing and relationship of observed signatures. The GEM Methods and Validation Resource Group helps those GEM focus group leaders running challenges to maximize participation and optimize scientific return from the significant time investment of these endeavors. This article gives a brief history of GEM community challenges and details those best practices that lead to an inclusive and valuable experience.

Working toward the goal of understanding solar wind (SW) entry to the Earth's magnetosphere, this study examines solar-origin ion composition in the magnetotail. During its trajectory, Wind spent a significant amount of time in the Earth's magnetotail, where its SupraThermal Ion Composition Spectrometer (STICS) measured the mass and mass per charge of protons, alpha particles, and heavy ions with an energy/charge ratio up to 226 keV/e. For this reason, STICS measurements within the magnetosphere from 1995 to 2002 help us identify preferential entry between the different SW ion species. This study statistically analyzes how the density ratio between SW heavy ions and alpha particles ([O6+ + C5+ + Fe10+]/He2+) varies for different upstream conditions and locations within the magnetosphere: Interplanetary Magnetic Field (IMF) orientation, low versus high SW density (NSW), low versus high SW dynamic pressure (PDyn), slow versus fast SW (VSW), and dawn versus dusk. Our results indicate that the SW heavies enter the magnetosphere more efficiently than He2+ during northward IMF and high NSW. In addition, these ratios exhibit a dawn-dusk asymmetry, highly skewed toward the dawn side for most upstream cases likely due to charge-exchange processes.

In the recent geological past, Earth's magnetic field reduced to ~10% of the modern values and the magnetic poles shifted away from the geographic poles, causing the Laschamps geomagnetic excursion, about 41 millennia ago. The excursion lasted ~2000 years, with dipole strength reduction and tilting spanning 300 years. During this period, the geomagnetic field's multipolarity resembled outer planets, causing rapid magnetospheric changes. To our knowledge, this study presents the first space plasma analysis of the excursion, linking the geomagnetic field, magnetospheric system, and upper atmosphere in sequence using feedback channels for distinct temporal epochs. A three-dimensional reconstruction of Earth's geospace system shows that these shifts affected auroral regions and open magnetic field lines, causing them to expand and wander toward lower latitudes. These changes likely altered the upper atmosphere's composition and influenced anthropological progress during that era. Looking through a modern lens, such an event would disrupt contemporary technology, including communications and satellite infrastructure.

Auroral precipitation plays an important role in the magnetosphere-ionosphere-thermosphere (MIT) coupling. Various precipitation spectra have been observed and they are driven by different physical mechanisms. In this study, we report the Dragon King model which is used to characterize auroral precipitation and its consequent ionospheric conductance in the Multiscale Atmosphere-Geospace Environment (MAGE) model, a newly developed whole geospace model. Mono-energetic electron precipitation is derived from large-scale field-aligned currents and drift-physics informed loss cone rate, using the linearized Fridman-Lemaire relation. Diffuse electron precipitation is derived with a drift-physics based ring current model, in which electron lifetime due to interactions with chorus and hiss waves is obtained with an empirical table and electron loss rate is informed by drift physics and IGRF magnetic field. Broadband electron precipitation is derived from a statistical relationship between field-aligned Alfvénic Poynting flux and the precipitation energy flux and number flux. The Dragon King model is validated from different perspectives with various observational data, including the statistical pattern during different categories of solar wind driving conditions, and along-trajectory comparison with satellite measurements. The Dragon King model is further used to understand the drivers of different precipitation and their relative importance with MAGE simulations.

The inductive component of the magnetospheric electric field, which is associated with the temporal change of magnetic field, provides an additional means of local plasma energization and transport in addition to the electrostatic counterpart. This study examines the detailed response of the inner magnetosphere to inductive electric fields and the associated electric-driven convection corresponding to different solar wind conditions. A novel modeling capability is employed to self-consistently simulate the electromagnetic and plasma environment of the entire magnetospheric cavity. The explicit separation of the electric field by source (inductive vs. electrostatic) and subsequent implementation of inductive effects in the ring current model allow us to investigate, for the first time, the effect of the inductive electric field on the kinetics and evolution of the ring current system. The simulation results presented in this study demonstrate that the inductive component of the electric field is capable of providing an additional source for long-lasting plasma drifts, which in turn significantly alter the trajectories of both thermal and energetic particles. Such changes in the plasma drift, which arise due to the inductive electric fields, further reshape the storm-time ring current morphology and alter the degree of the ring current asymmetry, as well as the timing and the peak of the ion pressure. The total ion energy is increasing at a faster rate than the supply of energetic ions to the ring current, suggesting that the inductive electric field provides effective and accumulative local energization for the trapped ring current population without confining additional particles.

AbstractWe present the first high resolution global MHD with coupled inner magnetosphere simulation results of an observed theta aurora event. We use the Space Weather Modeling Framework in the Geospace configuration, which produces accurate field aligned current closure in the ionosphere that is integral to theta aurora formation. At the location of the observed theta aurora, the simulation produces a narrow channel of Joule heating along both open and closed field lines, and between a pair of oppositely directed field‐aligned current sheets in the ionosphere. We demonstrate that this Joule heating pattern that we identify as theta aurora maps to a reconnection region at the magnetotail flanks as well as in the distant magnetotail. The theta aurora maps to a cross‐tail current disruption and field‐aligned current source region in a highly twisted magnetotail.

To mitigate the issues of inequity, exclusion, and a lack of diversity in the solar and space physics research community, a Research Topic collection gathered articles of how scientists in this discipline are taking strides to make this community more welcoming. This review summarizes the key advice from those articles and offers practical actions for both immediate and long-term implementation. There are six major topical categories into which the collection’s article can be grouped: early-year improvements (pre-college and undergraduate); inclusive project teams; diversity in awards; equity in hiring and promotion; leadership development; and the workplace environment. The scope of suggestions ranges from the very localized, such as the language choices we make in everyday conversations, to the institutional, such as the establishment of codes of conduct with a definition and enforcement of consequences for inappropriate behavior regarding inclusion and equity issues. It is hoped that the recommendations are applicable not only to the space physics community but also to others.

Abstract Regression models (LEEMYR: Low Energy Electron MLT geosYnchronous orbit Regression) predict hourly 4.1–30 keV electron flux at geostationary orbit (GOES‐16) using solar wind, IMF, and geomagnetic index parameters. Multiplicative interaction and polynomial terms describe synergistic and nonlinear effects. We reduce predictors to an optimal set using stepwise regression, resulting in models with validation comparable to a neural network. Models predict 1, 3, 6, 12, and 24 hr into the future. Validation correlations are as high as 0.78 (4.1 and 11 keV, 1 hr prediction) and Heidke Skill scores (HSS) up to 0.66. A 3 hr ahead prediction is more practical, with slightly lower validation correlation (0.75) and HSS (0.61). The addition of location (MLT: magnetic local time) as a covariate, including multiplicative interaction terms, accounts for location‐dependent flux differences and variation of parameter influence, and allows prediction over the full orbit. Adding a substorm index (SME) provides minimal increase in validation correlation (0.81) showing that other parameters are good proxies for an unavailable real time substorm index. Prediction intervals on individual values provide more accurate assessments of model quality than confidence intervals on the mean values. An inverse N‐weighted least squares approach is impractical as it increases false positive warnings. Physical interpretations are not possible as spurious correlations due to common cycles are not removed. However, SME, Bz, Kp, and Dst are the highest correlates of electron flux, with solar wind velocity, density, and pressure, and IMF magnitude being less well correlated.

In this study, a detailed metric survey on the “Galaxy 15” (April 2010) space weather event is conducted to validate MAGNetosphere–Ionosphere–Thermosphere (MAGNIT), a semi-physical auroral ionospheric conductance model characterizing four precipitation sources, against AMPERE measurements via field-aligned current (FAC) characteristics. As part of this study, the comparative performance of three ionosphere electrodynamic specifications involving auroral conductance models, MAGNIT, Ridley Legacy Model (RLM) (empirical), and Conductance Model for Extreme Events (CMEE) (empirical), within the Space Weather Modeling Framework (SWMF), is demonstrated. Overall, MAGNIT exhibits marginally improved predictions; root mean square error values in upward and downward FACs of MAGNIT predictions compared to AMPERE data are smaller than those of CMEE and Ridley Ionosphere Model (RIM) by ∼12.7% and ∼6.24% before the storm, ∼4.52% and ∼2.13% better during the main phase, ∼1.98% and ∼1.27% worse during the second minimum, and better by ∼1.84% and ∼1.49% by the beginning of the recovery, respectively. In all three model configurations, the dusk and night magnetic local time (MLT) sectors over-predict throughout the storm, while the day and dawn MLT sectors under-predict in response to interplanetary magnetic field (IMF) conditions. In addition to accuracy and bias, similar results and conclusions are drawn from additional metrics, including in the categories of correlation, precision, extremes, and skill, and recommendations are made for the best-performing model configuration in each metric category. Visual data–model comparisons conducted by studying the FAC location and latitude/MLT spread throughout various phases of the storm suggest that the spatial extent of the FACs is captured relatively well in the night-side auroral oval, unlike in the day-side oval. The spread in latitude of the FACs matches that in the previous literature on other model performances. This information on auroral precipitation sources and their weight on FACs, along with metrics from model–data comparisons, can be used to modify MAGNIT settings to optimize SWMF model performance.

AbstractElectron fluxes in the keV energy range can cause significant spacecraft surface charging, which in turn can affect the functioning of spacecraft components. In this paper, the geostationary electron fluxes measured by the satellites GOES 13‐18 in the energy range 2–200 keV are analyzed in order to look for their dependence on solar wind conditions. For this purpose, a range of solar wind parameters, IMF parameters and geomagnetic indices are examined, to look for the parameters which most significantly affect the electron flux. The analysis includes fluxes in the lower energy range of 2–40 keV, measured by GOES 16‐18, which have not been analyzed before. The measured electron fluxes are averaged over all directions, and high‐pass filtered to isolate variations shorter than 1 month. The analysis concentrates of the dawn sector, where variations are largest. A number of solar wind parameters and magnetic indices are analyzed concurrently with the electron flux data, to look for the most significant correlations between them. Most parameters have the highest correlation with electron flux when shifted in time by a certain delay. In addition to the different solar wind parameters and magnetic indices, combinations of different parameters are also examined for their best correlation with the electron flux. The most significant driving parameters are found to be the auroral electrojet index, combined with either the solar wind plasma velocity or the plasma density. The relative contribution of each of these parameters depends on electron energy, and differs between periods of high and low flux.

This report briefly summarizes the key mentors in my scientific career and some lessons learned from those influential people. My primary advice to others: it is okay to do something wrong. By doing science we are doing something hard that, by definition, has not been done before. I believe that impostor syndrome is a real threat to researcher wellbeing and we should acknowledge its presence and support each other to get through it. Regarding an approach to science, I encourage you to get started and make something bad. Also, take time for yourself, it really does help your productivity. To lead others, I recommend to be enthusiastic, actively listen, and make connections across disciplines. I think it is important to foster creativity in those around you. I advocate that you actively make the future that you want to have.

The Magnetospheric Auroral Asymmetry Explorer (MAAX) mission makes a major leap forward in determining how magnetosphereionosphere electrodynamic coupling regulates multi-scale auroral energy flow through the near-Earth space environment. Recently proposed to NASA’s Heliophysics Small Explorer program, MAAX accomplishes this by: (1) Understanding how seasons and tilt of the magnetic field regulate energy flow from the solar wind through the system; (2) discovering how the formation, evolution, and interhemispheric asymmetries of nightside meso-scale auroral features are regulated by the auroral background conductance; (3) determining how the time-dependent magnetospheric energy flow controls multi-scale auroral dynamics. The solar wind energy enters the magnetosphere mainly through dayside reconnection and is stored in the magnetosphere, which later converts to plasma and neutral thermal and kinetic energies. Dynamic smaller-scale processes in the nightside magnetosphere map from the magnetosphere to the ionosphere, resulting in auroral structures that have fascinated people for millennia. Observations of the aurora have been used as a window to probe and understand these dynamics even beyond the Earth system. The magnetic field lines in which the aurora occurs thread through both hemispheres. Traditionally, auroral observations from one hemisphere are assumed to be conjugate, while recent observations suggest this may not always be applicable. With auroral observations from one hemisphere, we can only understand some of the processes that control the flow of energy through the system. However, with observations in both with observations in both hemispheres we gain a deeper understanding into the dynamics of this integrated system. MAAX comprises two observatories in circular polar orbits at 20,850 km altitude for viewing of the auroral ovals in both hemispheres. Each observatory carries a single high-heritage UV imager to close the science objectives that operate poleward of +/-35° latitude. For the first year of the mission, the observatories are spaced at 90° to allow continuous coverage on one oval, then the other with a 6-hour duty cycle. This phase also allows for intervals in which both view the same hemisphere or both view the same longitude but different hemispheres. For the second year of the mission, the observatories are spaced at 180° to have simultaneous complete viewing of both the northern and southern auroral ovals with a 4.5 hr/1.5 hr on/off duty cycle. Discussed here is the science motivation of the mission concept and the numerical modeling trade studies to optimize the mission characteristics to achieve the proposed objectives.

Key Points:• First-principles, self-consistent geospace modeling will require at least exascale-level computing capabilities; however, the technical skills necessary to develop such simulation codes are not taught as part of Heliophysics training/PhD programs.• Developing exascale Heliophysics codes will require transdisciplinary collaborations between physicists, computer scientists, software engineers, data scientists, and applied mathematics.Such teams must be persistent and formed around specific skills, not specific problems.• We must have stable, positive long-term career outcomes for Heliophysics scientific developers in order to retain knowledge of and promote future innovation in scientific algorithm development and advanced computing techniques.One such way to do this is by funding long-term scientific programming groups, akin to Heliophysics DRIVE Centers.• We must have a balance between promoting innovation via funding short-term closed-source development and allowing the open-source community to benefit from and build on the newest scientific modeling techniques.