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Journal articleGershman DJ, Fuselier SA, Cohen IJ, et al., 2024,
Magnetic Reconnection at Planetary Bodies and Astrospheres
, SPACE SCIENCE REVIEWS, Vol: 220, ISSN: 0038-6308 -
Journal articleLaker R, Horbury TS, O'Brien H, et al., 2024,
Using Solar Orbiter as an Upstream Solar Wind Monitor for Real Time Space Weather Predictions
, SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS, Vol: 22 -
Journal articleLouarn P, Fedorov A, Prech L, et al., 2024,
Skewness and kurtosis of solar wind proton distribution functions: The normal inverse-Gaussian model and its implications
, ASTRONOMY & ASTROPHYSICS, Vol: 682, ISSN: 0004-6361 -
Journal articleWells CD, Kasoar M, Ezzati M, et al., 2024,
Significant human health co-benefits of mitigating African emissions
, Atmospheric Chemistry and Physics, Vol: 24, Pages: 1025-1039, ISSN: 1680-7316Future African aerosol emissions, and therefore air pollution levels and health outcomes, are uncertain and understudied. Understanding the future health impacts of pollutant emissions from this region is crucial. Here, this research gap is addressed by studying the range in the future health impacts of aerosol emissions from Africa in the Shared Socioeconomic Pathway (SSP) scenarios, using the UK Earth System Model version 1 (UKESM1), along with human health concentration-response functions. The effects of Africa following a high-pollution aerosol pathway are studied relative to a low-pollution control, with experiments varying aerosol emissions from industry and biomass burning. Using present-day demographics, annual deaths within Africa attributable to ambient particulate matter are estimated to be lower by 150 000 (5th-95th confidence interval of 67 000-234 000) under stronger African aerosol mitigation by 2090, while those attributable to O3 are lower by 15 000 (5th-95th confidence interval of 9000-21 000). The particulate matter health benefits are realised predominantly within Africa, with the O3-driven benefits being more widespread - though still concentrated in Africa - due to the longer atmospheric lifetime of O3. These results demonstrate the important health co-benefits from future emission mitigation in Africa.
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Journal articleKrupar V, Kruparova O, Szabo A, et al., 2024,
Comparative Analysis of Type III Radio Bursts and Solar Flares: Spatial Localization and Correlation with Solar Flare Intensity
, ASTROPHYSICAL JOURNAL, Vol: 961, ISSN: 0004-637X -
Journal articleChen L, Ma B, Wu D, et al., 2024,
Weak Solar Radio Bursts from the Solar Wind Acceleration Region Observed by the Parker Solar Probe and Its Probable Emission Mechanism
, ASTROPHYSICAL JOURNAL, Vol: 961, ISSN: 0004-637X -
Journal articleMcmanus MD, Klein KG, Bale SD, et al., 2024,
Proton- and Alpha-driven Instabilities in an Ion Cyclotron Wave Event
, ASTROPHYSICAL JOURNAL, Vol: 961, ISSN: 0004-637X -
Journal articleHosner M, Nakamura R, Schmid D, et al., 2024,
Reconnection inside a Dipolarization Front of a diverging Earthward fast flow
, JGR: Space Physics, Vol: 129, ISSN: 2169-9402We examine a Dipolarization Front (DF) event with an embedded electron diffusion region (EDR), observed by the Magnetospheric Multiscale (MMS) spacecraft on 08 September 2018 at 14:51:30 UT in the Earth's magnetotail by applying multi-scale multipoint analysis methods. In order to study the large-scale context of this DF, we use conjunction observations of the Cluster spacecraft together with MMS. A polynomial magnetic field reconstruction technique is applied to MMS data to characterize the embedded electron current sheet including its velocity and the X-line exhaust opening angle. Our results show that the MMS and Cluster spacecraft were located in two counter-rotating vortex flows, and such flows may distort a flux tube in a way that the local magnetic shear angle is increased and localized magnetic reconnection may be triggered. Using multi-point data from MMS we further show that the local normalized reconnection rate is in the range of R ∼ 0.16 to 0.18. We find a highly asymmetric electron in- and outflow structure, consistent with previous simulations on strong guide-field reconnection events. This study shows that magnetic reconnection may not only take place at large-scale stable magnetopause or magnetotail current sheets but also in transient localized current sheets, produced as a consequence of the interaction between the fast Earthward flows and the Earth's dipole field.
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Journal articleSmith AW, Rae IJ, Stawarz JE, et al., 2024,
Automatic Encoding of Unlabeled Two Dimensional Data Enabling Similarity Searches: Electron Diffusion Regions and Auroral Arcs
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 129, ISSN: 2169-9380 -
Journal articleQuilelli Correa Rocha Ribeiro R, Gryspeerdt E, van Reeuwijk M, 2023,
Retrieving cloud sensitivity to aerosol using ship emissions in overcast conditions
, Geophysical Research Letters, Vol: 50, ISSN: 0094-8276The interaction between aerosols and clouds is one of the major uncertainties in past climate change, affecting the accuracy of future climate projections. Ship tracks, trails left in clouds through the addition of aerosol in the ship exhaust plume, have become a key observational tool for constraining aerosol-cloud interactions. However, manyexpected tracks remain undetected, presenting a significant gap in current knowledge of aerosol forcing. Here we leverage a plume-parcel model to simulate the impact of aerosol dispersion for 2957 cases off California’s coast on cloud droplet number concentration (CDNC) enhancements. Plume-parcel models show a large sensitivity to updraft uncertainties, which are found to be a primary control on track formation. Using these plume-parcel models, updraft values consistent with observed CDNC enhancements are recovered, suggesting that relying solely on cloud-top radiative cooling may overestimate in-cloud updrafts by around 50%, hence overstating the cloud sensitivity to aerosols.
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Journal articleLaker R, Horbury TS, Woodham LD, et al., 2023,
Coherent deflection pattern and associated temperature enhancements in the near-Sun solar wind
, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 527, Pages: 10440-10447, ISSN: 0035-8711 -
Journal articleJebaraj IC, Dresing N, Krasnoselskikh V, et al., 2023,
Relativistic electron beams accelerated by an interplanetary shock
, ASTRONOMY & ASTROPHYSICS, Vol: 680, ISSN: 0004-6361 -
Journal articleClear CP, Pickering JC, Nave G, et al., 2023,
Wavelengths and Energy Levels of the Upper Levels of Singly Ionized Nickel (Ni <sc>ii</sc>) from 3<i>d</i> <SUP>8</SUP>(<SUP>3</SUP> <i>F</i>)5<i>f</i> to 3<i>d</i> <SUP>8</SUP>(<SUP>3</SUP> <i>F</i>)9<i>s</i>
, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 269, ISSN: 0067-0049 -
Journal articleKuzichev IV, Vasko IY, Artemyev AV, et al., 2023,
Particle-in-Cell Simulations of Sunward and Anti-sunward Whistler Waves in the Solar Wind
, ASTROPHYSICAL JOURNAL, Vol: 959, ISSN: 0004-637X -
Journal articleWilson III LB, Stevens ML, Kasper JC, et al., 2023,
The Statistical Properties of Solar Wind Temperature Parameters Near 1 au (vol 236, 41, 2018)
, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 269, ISSN: 0067-0049 -
Journal articleSishtla CP, Jebaraj IC, Pomoell J, et al., 2023,
The Effect of the Parametric Decay Instability on the Morphology of Coronal Type III Radio Bursts
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 959, ISSN: 2041-8205 -
Journal articleKrasnoselskikh V, Zaslavsky A, Artemyev A, et al., 2023,
Ion Kinetics of Plasma Interchange Reconnection in the Lower Solar Corona
, ASTROPHYSICAL JOURNAL, Vol: 959, ISSN: 0004-637X -
Journal articleGiacalone J, Cohen CMS, Mccomas DJ, et al., 2023,
Analyses of ∼0.05-2 MeV Ions Associated with the 2022 February 16 Energetic Storm Particle Event Observed by Parker Solar Probe
, ASTROPHYSICAL JOURNAL, Vol: 958, ISSN: 0004-637X -
Journal articleLorfing CY, Reid HAS, Gomez-Herrero R, et al., 2023,
Solar Electron Beam-Langmuir Wave Interactions and How They Modify Solar Electron Beam Spectra: Solar Orbiter Observations of a Match Made in the Heliosphere
, ASTROPHYSICAL JOURNAL, Vol: 959, ISSN: 0004-637X -
Journal articleRasca AP, Farrell WM, Gruesbeck JR, et al., 2023,
Switchbacks and Associated Magnetic Holes Observed near the Alfvén Critical Surface
, ASTROPHYSICAL JOURNAL, Vol: 959, ISSN: 0004-637X -
Journal articleRosenfeld D, Kokhanovsky A, Goren T, et al., 2023,
Frontiers in satellite‐based estimates of cloud‐mediated aerosol forcing
, Reviews of Geophysics, Vol: 61, ISSN: 8755-1209Atmospheric aerosols affect the Earth's climate in many ways, including acting as the seeds on which cloud droplets form. Since a large fraction of these particles is anthropogenic, the clouds' microphysical and radiative characteristics are influenced by human activity on a global scale leading to important climatic effects. The respective change in the energy budget at the top of the atmosphere is defined as the effective radiative forcing due to aerosol-cloud interaction (ERFaci). It is estimated that the ERFaci offsets presently nearly 1/4 of the greenhouse-induced warming, but the uncertainty is within a factor of two. A common method to calculate the ERFaci is by the multiplication of the susceptibility of the cloud radiative effect to changes in aerosols by the anthropogenic change of the aerosol concentration. This has to be done by integrating it over all cloud regimes. Here we review the various methods of the ERFaci estimation. Global measurements require satellites' global coverage. The challenge of quantifying aerosol amounts in cloudy atmospheres are met with the rapid development of novel methodologies reviewed here. The aerosol characteristics can be retrieved from space based on their optical properties, including polarization. The concentrations of the aerosols that serve as cloud drop condensation nuclei can be also estimated from their impact on the satellite-retrieved cloud drop number concentrations. These observations are critical for reducing the uncertainty in the ERFaci calculated from global climate models (GCMs), but further development is required to allow GCMs to properly simulate and benefit these novel observables.
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Journal articleHwang K-J, Nakamura R, Eastwood JP, et al., 2023,
Cross-scale processes of magnetic reconnection
, Space Science Reviews, Vol: 219, ISSN: 0038-6308Various physical processes in association with magnetic reconnection occur over multiple scales from the microscopic to macroscopic scale lengths. This paper reviews multi-scale and cross-scale aspects of magnetic reconnection revealed in the near-Earth space beyond the general global-scale features and magnetospheric circulation organized by the Dungey Cycle. Significant and novel advancements recently reported, in particular, since the launch of the Magnetospheric Multi-scale mission (MMS), are highlighted being categorized into different locations with different magnetic topologies. These potentially paradigm-shifting findings include shock and foreshock transient driven reconnection, magnetosheath turbulent reconnection, flow shear driven reconnection, multiple X-line structures generated in the dayside/flankside/nightside magnetospheric current sheets, development and evolution of reconnection-driven structures such as flux transfer events, flux ropes, and dipolarization fronts, and their interactions with ambient plasmas. The paper emphasizes key aspects of kinetic processes leading to multi-scale structures and bringing large-scale impacts of magnetic reconnection as discovered in the geospace environment. These key features can be relevant and applicable to understanding other heliospheric and astrophysical systems.
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Journal articleHartinger MD, Elsden T, Archer MO, et al., 2023,
Properties of Magnetohydrodynamic normal modes in the Earth's magnetosphere
, JGR: Space Physics, Vol: 128, ISSN: 2169-9402The Earth's magnetosphere supports a variety of Magnetohydrodynamic (MHD) normal modes with Ultra Low Frequencies (ULF) including standing Alfvén waves and cavity/waveguide modes. Their amplitudes and frequencies depend in part on the properties of the magnetosphere (size of cavity, wave speed distribution). In this work, we use ∼13 years of Time History of Events and Macroscale Interactions during Substorms satellite magnetic field observations, combined with linearized MHD numerical simulations, to examine the properties of MHD normal modes in the region L > 5 and for frequencies <80 mHz. We identify persistent normal mode structure in observed dawn sector power spectra with frequency-dependent wave power peaks like those obtained from simulation ensemble averages, where the simulations assume different radial Alfvén speed profiles and magnetopause locations. We further show with both observations and simulations how frequency-dependent wave power peaks at L > 5 depend on both the magnetopause location and the location of peaks in the radial Alfvén speed profile. Finally, we discuss how these results might be used to better model radiation belt electron dynamics related to ULF waves.
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Journal articleKlein KG, Spence H, Alexandrova O, et al., 2023,
HelioSwarm: a multipoint, multiscale mission to characterize turbulence
, Space Science Reviews, Vol: 219, ISSN: 0038-6308HelioSwarm (HS) is a NASA Medium-Class Explorer mission of the Heliophysics Division designed to explore the dynamic three-dimensional mechanisms controlling the physics of plasma turbulence, a ubiquitous process occurring in the heliosphere and in plasmas throughout the universe. This will be accomplished by making simultaneous measurements at nine spacecraft with separations spanning magnetohydrodynamic and sub-ion spatial scales in a variety of near-Earth plasmas. In this paper, we describe the scientific background for the HS investigation, the mission goals and objectives, the observatory reference trajectory and instrumentation implementation before the start of Phase B. Through multipoint, multiscale measurements, HS promises to reveal how energy is transferred across scales and boundaries in plasmas throughout the universe.
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Journal articleDimmock AP, Gedalin M, Lalti A, et al., 2023,
Backstreaming ions at a high Mach number interplanetary shock Solar Orbiter measurements during the nominal mission phase
, ASTRONOMY & ASTROPHYSICS, Vol: 679, ISSN: 0004-6361 -
Journal articleAfanasiev A, Vainio R, Trotta D, et al., 2023,
Self-consistent modeling of the energetic storm particle event of November 10, 2012
, ASTRONOMY & ASTROPHYSICS, Vol: 679, ISSN: 0004-6361 -
Journal articleEglinton TI, Graven HD, Raymond PA, et al., 2023,
A special issue preface: radiocarbon in the Anthropocene
, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol: 381, ISSN: 1364-503XThe Anthropocene is defined by marked acceleration in human-induced perturbations to the Earth system. Anthropogenic emissions of CO2 and other greenhouse gases to the atmosphere and attendant changes to the global carbon cycle are among the most profound and pervasive of these perturbations. Determining the magnitude, nature and pace of these carbon cycle changes is crucial for understanding the future climate that ecosystems and humanity will experience and need to respond to. This special issue illustrates the value of radiocarbon as a tool to shed important light on the nature, magnitude and pace of carbon cycle change. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'.
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Journal articleEglinton TI, Graven HD, Raymond PA, et al., 2023,
Making the case for an International Decade of Radiocarbon
, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol: 381, ISSN: 1364-503XRadiocarbon (14C) is a critical tool for understanding the global carbon cycle. During the Anthropocene, two new processes influenced 14C in atmospheric, land and ocean carbon reservoirs. First, 14C-free carbon derived from fossil fuel burning has diluted 14C, at rates that have accelerated with time. Second, 'bomb' 14C produced by atmospheric nuclear weapon tests in the mid-twentieth century provided a global isotope tracer that is used to constrain rates of air-sea gas exchange, carbon turnover, large-scale atmospheric and ocean transport, and other key C cycle processes. As we write, the 14C/12C ratio of atmospheric CO2 is dropping below pre-industrial levels, and the rate of decline in the future will depend on global fossil fuel use and net exchange of bomb 14C between the atmosphere, ocean and land. This milestone coincides with a rapid increase in 14C measurement capacity worldwide. Leveraging future 14C measurements to understand processes and test models requires coordinated international effort-a 'decade of radiocarbon' with multiple goals: (i) filling observational gaps using archives, (ii) building and sustaining observation networks to increase measurement density across carbon reservoirs, (iii) developing databases, synthesis and modelling tools and (iv) establishing metrics for identifying and verifying changes in carbon sources and sinks. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'.
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Journal articleSishtla CP, Pomoell J, Vainio R, et al., 2023,
Modelling the interaction of Alfvenic fluctuations with coronal mass ejections in the low solar corona
, ASTRONOMY & ASTROPHYSICS, Vol: 679, ISSN: 0004-6361 -
Journal articleBizien N, de Wit TD, Froment C, et al., 2023,
Are Switchback Boundaries Observed by Parker Solar Probe Closed?
, ASTROPHYSICAL JOURNAL, Vol: 958, ISSN: 0004-637X
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