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Journal articleArcher M, Southwood D, Zhang S, et al., 2027,
Characterising mesoscale magnetopause surface waves within magnetosphere--ionosphere--groundcoupling
, Annales Geophysicae, Vol: 44, Pages: 595-630, ISSN: 0992-7689Disturbances to the magnetopause location driven by upstream pressure variations or flow shear instabilities may be described as surface waves, which act as localised sources of field-aligned currents coupling the magnetosphere to the ionosphere. However, their impacts on the ionosphere and ground across representative ranges of wave and system properties are poorly understood. We, therefore, develop a simple numerical model for dispersionless mesoscale magnetopause surface waves within the coupled magnetosphere–ionosphere–ground system to gain insight into how their amplitudes and spatial scales throughout the system might vary with conditions. In general, the impacts of finite wave packets can be decomposed into periodic fluctuations (with matching wavelength to that directly above in the magnetosphere) along with slowly-varying trends that result from finite wave effects. Finite wave packets act in the far-field like a string of alternating field-aligned currents well described both in the ionosphere and on the ground as a two-dimensional current dipole. In the ionosphere, near-field periodic fluctuations exponentially decay over the reduced wavelength latitudinally away from the projected magnetopause boundary layer flux tubes, which may limit how well they can be resolved by radar. The relationship between the magnetic field above and below the ionosphere becomes more complicated for surface waves than infinite plane Alfvén waves due to the additional spatial structure, which introduces interference across the spectrum of wavenumbers present. This modifies how the ionosphere screens, rotates, and spatially smears magnetic field perturbations across all three components in different ways. For mesoscale wavelengths this importantly results in latitudinal scales of amplitude and polarisation variation smaller than typical ground magnetometer spacings, motivating the need for denser networks. A range of effective skin depths in the ground are app
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Journal articleZelinka MD, Myers TA, Qin Y, et al., 2026,
Recent cloud trends and extremes reaffirm established bounds on cloud feedback and aerosol-cloud interactions
, Communications Earth and Environment, Vol: 7Earth’s energy imbalance has increased markedly over the past two decades, reaching a record in 2023. Both the long-term trend and year-to-year variations are linked to reduced reflection of sunlight by low-level clouds, which is pronounced over Northern Hemisphere oceans. However, the causes of these cloud changes and their implications for future Earth system evolution are unknown, raising concerns about a stronger-than-expected cloud feedback. Here we quantify the meteorological factors behind interannual cloud-radiative anomalies, several of which aligned to produce the extreme 2023 value. These meteorological variations are superposed on a background of declining sulfate aerosol concentrations, contributing to a sustained decrease in cloud reflection over the past 22 years. The resulting constraints on cloud feedback and aerosol forcing are consistent with previous studies, supporting an equilibrium climate sensitivity near 3<sup>∘</sup>C (likely range 2.7–4.1<sup>∘</sup>C). Thus, recent observations do not indicate an emerging stronger cloud feedback or underestimated future warming.
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Journal articleAuestad H, Shibu A, Ceppi P, et al., 2026,
The latent heating feedback effect on storm tracks in current and future climates
, Npj Climate and Atmospheric Science, Vol: 9Extratropical storms release latent heat as they transport warm, moist air poleward and upward. That latent heating feeds back on storms by intensifying individual cyclones and by altering the environmental conditions for the growth of storms, constituting a latent heating-dynamics feedback. As the climate warms, storm-track latent heating increases, but the role of this feedback in a future climate remains unclear. Using atmospheric general-circulation model experiments that separate the coupled heating-dynamics feedback from climatological changes in latent heating, we show that this feedback plays a leading-order role in intensifying storm tracks under +4 K warming. The feedback increases lower-tropospheric storm intensity, compensating for reduced baroclinicity, while its upper-tropospheric effect is seasonal: amplifying summer eddies but damping winter ones. The feedback is critical for storms that grow in moist environments, typical for summer and warmer climates, underscoring the need for accurate representation of moist processes in climate models.
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Journal articleDing M, Darvariu VA, Ryabtsev AN, et al., 2026,
Accelerating atomic fine structure determination with graph reinforcement learning
, Communications Physics, Vol: 9Atomic data determined by analysis of observed atomic spectra are essential for plasma diagnostics. For each low-ionisation open d- and f-subshell atomic species, around 10<sup>3</sup> fine structure energy levels can be determined through years of analysis of 10<sup>4</sup> observable spectral lines. We propose a partial automation of this task by casting the analysis procedure as a Markov decision process and solving it by graph reinforcement learning using reward functions partly learned on historical human decisions. In our evaluations on existing spectral line lists and theoretical calculations for Co II, Nd II and Nd III, hundreds of energy levels were identified and determined in hours, agreeing with published values in 95% of cases for Co II and 54–87% for Nd II and Nd III. As the current efficiency in atomic fine structure determination struggles to meet growing atomic data demands, our artificial intelligence approach sets the stage for closing this gap.
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Journal articleCargill PJ, Hood AW, Johnson D, 2026,
Plasma cooling by thermal conduction in the magnetically closed solar corona with large spatial variations in the magnetic field strength
, Monthly Notices of the Royal Astronomical Society, Vol: 551, ISSN: 0035-8711Plasma cooling by thermal conduction is considered for solar coronal magnetic loops that have large variations in their magnetic field strength and hence cross-sectional area. In terms of a ‘cooling time’, for all cases considered an increase in the cross sectional area from base to apex leads to longer cooling times than for a loop with uniform area. Although this result is expected, this paper reveals, for the first time, a vast range of different cooling outcomes that depend on the details of the prescribed loop geometry. While a simple approach suggests that the cooling time could scale with the average area, ⟨ A ⟩ , this only holds when the region of the most significant area variation and the hottest plasma coincide. Instead, analytic and quasi-analytic solutions show that this scaling can greatly exaggerate the effect of ⟨ A ⟩ on the cooling time. For example, there are cases in which the cooling time scales as ln (⟨ A ⟩ ) . Thus, conductive cooling needs to be considered on a case-by-case basis. The results can be understood in terms of an artificial ‘heating’ associated with a non-uniform loop area.
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Journal articleEmber W, Pulupa M, Martinović M, et al., 2026,
Electron Shot Noise on a Current Biased Antenna
, Geophysical Research Letters, Vol: 53, ISSN: 0094-8276The Parker Solar Probe (PSP) Fields Experiment (FIELDS) uses Radio Frequency Spectrometer (RFS) data and Quasi-Thermal Noise Spectroscopy (QTN) to determine the temperature and density of electrons in the heliosphere. The FIELDS antennas typically operate with a negative bias current. We quantify the effect of the bias current on the shot noise spectrum by comparing spectra with a nominal negative bias current and spectra with minimal bias. The observed increase in the shot noise spectrum is smaller than the value determined by calculating currents based on measured instrument and plasma parameters. We discuss possible reasons for this discrepancy, and describe how quantifying the effects of the applied bias current on the shot noise spectrum can enable more accurate QTN spectroscopy.
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Journal articleBoyce I, Cicirello A, Gryspeerdt E, 2026,
Sensitivity of bi-spectral retrievals to the fixed effective variance assumption in ship tracks
, Atmospheric Measurement Techniques, Vol: 19, Pages: 5475-5490<jats:p>Abstract. Ship tracks, bright lines in clouds formed by ship exhaust, serve as “natural laboratories” for investigating aerosol-cloud interactions, one of the largest sources of uncertainty in the human forcing of the climate. Observing ship tracks has been used to help constrain the effect of anthropogenic aerosols on cloud brightness, amount and water content. The validity of these constraints relies, in part, on the accuracy of satellite retrieval algorithms used to measure cloud properties. A known source of uncertainty in these algorithms is the representation of the droplet size distribution. Standard bi-spectral retrievals (e.g. MODIS) rely on a fixed effective variance (veff) for the modified gamma distribution used to model cloud droplet dispersion. The introduction of aerosols into clean, marine clouds produces not only smaller droplets but also a narrower size distribution, contradicting this fixed assumption. This study presents a controlled, synthetic retrieval experiment that isolates the sensitivity of cloud property retrievals, and the derived aerosol-cloud interaction metrics, to this single assumption. This study uses idealised ship tracks as the test case because they provide the strongest realistic contrast between the assumed and true distribution widths. The results produced indicate that neglecting the narrowing of the droplet size distribution causes retrieved effective radius (re) to differ systematically between clean and polluted regimes. The polluted branch is overestimated relative to the near-unbiased clean branch by approximately 2.3 %–3.4 %, depending on the assumed retrieval baseline. Optical depth (τ) is virtually unaffected in either regime. LWP is retrieved with little bias in either regime, so the clean-to-polluted LWP contrast is largely preserved. Nd shows the opposite problem. The apparent clean-to-polluted increase in Nd is overstated by 22 %–23 % under bot
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Journal articleLaemmel T, Geissbühler D, Henne S, et al., 2026,
Radiocarbon in atmospheric CH <sub>4</sub> and CO <sub>2</sub> at Jungfraujoch in 2019–2024: influence of regional nuclear emissions and current global atmospheric <sup>14</sup> CH <sub>4</sub> signal
, Atmospheric Chemistry and Physics, Vol: 26, Pages: 12019-12036<jats:p>Abstract. Radiocarbon (14C) is a valuable tracer to determine the relative fossil fractions of emitted carbonaceous greenhouse gases, such as CO2 and CH4. While atmospheric Δ14CO2 measurements have been conducted at multiple sites for several decades, Δ14CH4 measurements remain more limited, mainly due to measurement challenges. In addition, 14CH4 emissions from nuclear power plants (NPPs) can complicate data interpretation. In this study, fortnightly Δ14CH4 and Δ14CO2 measurements at the Swiss High-Altitude Research Station Jungfraujoch (JFJ, about 3500 m a.s.l.) between 2019 and 2024 are presented. Over this period, Δ14CH4 values showed an increase from 350 ± 19 ‰ to 381 ± 13 ‰, while Δ14CO2 values decreased from −2.0 ± 3.8 ‰ to −12.7 ± 2.0 ‰, respectively. The former is related to the slight increase of 14CH4 emissions from the nuclear industry over the last years, while the latter is linked to the continued dilution of the 14CO2 signal due to the release of 14C-devoid CO2 from combustion of fossil fuels. Despite its high elevation, JFJ is still influenced by NPPs operating in Europe. To assess the nuclear 14C contribution to our individual measurements, we use a combination of in situ 222Radon measurements and Lagrangian particle dispersion model convolved with bottom-up inventory of 14C emissions from NPPs. Furthermore, our Δ14CH4 measurements reasonably agree with simulated atmospheric values of Δ14CH4 estimated by a global atmospheric one-box model and an estimation of global nuclear 14CH4 emissions.</jats:p>
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Journal articleKeeping TR, Zachariah M, Haas O, et al., 2026,
Attribution of the record breaking 2025 European fire season to climate change
, Natural Hazards and Earth System Sciences, Vol: 26, Pages: 3761-3813, ISSN: 1561-8633The 2025 European fire season was historically extreme, with record-breaking burned area exceeding 1 400 000 ha, and multiple regionally unprecedented wildfires. Emerging fire regimes and extreme wildfire behaviour in Europe pose increasing adaptation challenges. Extreme event attribution of a recent fire season, combined with analysis of changes in vegetation and land use, provides insight into the effect of climate and environmental change on high impact events. We analyse five regions that experienced particularly extreme wildfire activity in 2025 (northwestern Iberia, western and northern Britain, Occitania, the eastern Adriatic/Ionian, and northern and western Türkiye) capturing a diverse range of driving weather conditions and fire regimes. Strong trends towards drier summers and extreme weekly vapour pressure deficit (VPD) were found, with summer drought emergent from natural variability in most southern European regions, and VPD extreme emergent in reanalysis data for all regions. Changes in VPD are the main reason why combined hot, dry, and windy conditions have become more frequent than expected from natural variability. This emergence is seen in both reanalysis data and climate models for the Iberian, Adriatic/Ionian and Turkish regions. In contrast, in the British and Occitanian regions, models do not show observed trends.
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Journal articleErvin T, Bowen TA, Mallet A, et al., 2026,
Direct Measurement of Diffusion Coefficients: Evidence for Diffusive Stochastic Heating in Collisionless Plasmas.
, Phys Rev Lett, Vol: 137Open questions in collisionless plasma dissipation can be addressed using space-based observations in different astrophysical environments, with implications for both astrophysical and laboratory plasma systems. We study a low-β, highly imbalanced, sub-Alfvénic stream observed by Parker Solar Probe (PSP) to identify and distinguish between signatures of stochastic heating (SH) and resonant heating (RH) by parallel ion cyclotron waves (∥-ICWs). Prior work studying this stream [Trevor A. Bowen et al., Stochastic heating in the sub-Alfvénic solar wind, Phys. Rev. Lett. 135, 255201 (2025)PRLTAO0031-900710.1103/rxd8-22m9] showed that the SH rate, accounting for intermittency, matched the amplitude of the local energy transfer (LET) rate, while the RH rate did not. This comparison relied on a number of assumptions regarding the nature of the diffusive process and the calculation of the LET rate. We introduce a novel technique of inverting the proton guiding center equation to empirically measure velocity-space diffusion coefficients using three-dimensional proton velocity distribution functions, from the ion electrostatic analyzer (the Solar Probe Analyzer for Ions) on PSP. Measured diffusion coefficients are used to determine phase-space heating rates, leading to a calculation of a fully kinetic heating rate independent of assumptions made in prior work. We show that scale-dependent analytic expressions for SH via noncoherent fluctuations match the empirical measurements from PSP data, provided that we account for intermittency in the heating calculation. In contrast, the derived heating rates for SH that accounts for the effects of the helicity barrier and heating rates for RH via ∥-ICWs do not peak in the same region of velocity space as the empirical measurements, nor do they reach the required magnitude. Our approach provides novel methodology to uniquely identify and constrain heating processes in collisionless plasmas and shows evidence of a Fokk
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Journal articleLazzeri C, Forsyth C, Samsonov A, et al., 2026,
Excitation of large amplitude compressional ULF waves in the magnetosphere by solar wind pressure spikes and IMF southward turning
, Journal of Geophysical Research: Space Physics, Vol: 131, ISSN: 2169-9380We present a case study of large amplitude, compressional Pc5 waves observed by GOES 13 and 15 at geosynchronous orbit near noon. These waves were excited near the arrival time of two consecutive solar wind dynamic pressure spikes at the magnetopause, the second of which was associated with a large and rapid southward turning of the Interplanetary Magnetic Field (IMF). Magnetopause oscillations at a similar frequency were observed by the THEMIS spacecraft in the post-noon magnetosphere, however without clear signatures of compressional waves. The analysis of the ground response near the GOES foot-points, located close to the Churchill line of magnetometer stations, revealed an increase in wave power following each spike, with slight changes in polarizations. Following the second pressure spike's arrival at the magnetosphere, we found evidence of Field Line Resonances in the Northward component of the magnetic field, which suggests coupling with the compressional waves observed at GOES. We investigated potential Ultra Low Frequency drivers, and identified the most likely driving mechanism to be the drift-mirror instability; lack of appropriate measurements however prevented us from confirming this hypothesis.
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Journal articleSteinwand V, Stephenson P, Lewis ZM, et al., 2026,
Cometary ion dynamics at a weakly outgassing comet
, Monthly Notices of the Royal Astronomical Society, Vol: 550, ISSN: 0035-8711The ESA/Rosetta mission escorted comet 67P/Churyumov–Gerasimenko for 2 yr, exploring its plasma environment across diverse outgassing conditions. Plasma density observations from the Rosetta Plasma Consortium (RPC) are broadly categorized into two regimes for the ion dynamics, linked to the presence of a diamagnetic cavity at Rosetta’s location. With a diamagnetic cavity present, ions detected by Rosetta are accelerated with respect to the neutral coma. Without a diamagnetic cavity present, at lower outgassing, and nearer the nucleus, ions co-move with the neutrals. We examine the transition between regimes following Rosetta’s last detection of the cavity in 2016 February. During this transition, global 3D plasma models of the cometary ionosphere underestimate plasma densities. To investigate this underestimation, we assess the sensitivity of cometary ion densities to different parameters using a 3D collisional ion test particle model, driven by electromagnetic fields from hybrid modelling. We show that considering cometary electron cooling is necessary to model cometary ion dynamics within 100 km of the surface. Electron temperatures derived from collisional electron modelling affect ion dynamics via the ambipolar electric field, increasing ion number densities. We further show that the cometary electron cooling exobase organizes Rosetta plasma density observations; different ion dynamics regimes are linked to the position of Rosetta relative to the exobase. These findings demonstrate that Rosetta was below this exobase for much of the post-perihelion period. They justify the absence of ion acceleration in plasma density assessments and the use of uniform electron-impact ionization frequencies between Rosetta and the surface during post-perihelion.
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Journal articleYousuf F, Li Z, Bale SD, et al., 2026,
Joint Estimation of Properties of the Lunar Subsurface and Galactic Foregrounds with LuSEE-night
, Astronomical Journal, Vol: 172, ISSN: 0004-6256The Lunar Surface Electromagnetics Experiment (LuSEE-Night) is a joint NASA-DOE-ESA low-frequency radio telescope that will reach the lunar far side in 2027. The unknown dielectric properties of the subsurface at the LuSEE-Night landing site impose the most significant limitation for precision instrument calibration, as reflections from the lunar subsurface can change the primary beam at the 10%–20% level. Simulations of these effects have provided insight and concern, showing that the lunar subsurface modeled as a lossy dielectric can absorb a large amount of the power of the sky signal. While this absorption may not strongly impact the signal-to-noise ratio in a sky noise-dominated regime, it could complicate the beam pattern and make the signal more difficult to model and interpret. We have simulated the far-field properties of the LuSEE-Night beam for varying dielectric profiles of the lunar subsurface. We find that varying the properties of the lunar subsurface has the most significant impact around the antenna resonance, impacting its amplitude, position, and width. Conversely, changing the properties of the foreground impacts the data across the band. We use a Bayesian inference pipeline to jointly estimate parameters of a Galactic foreground model and dielectric properties of the lunar subsurface around the LuSEE-Night landing site and find that parameters of both the galaxy and subsurface properties can be estimated jointly. While the modeling is somewhat idealized, we believe that the results are largely robust owing to the fact that spectral variations for plausible subsurface and galaxy models have very different spectral signatures.
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Journal articleAcevski M, Achilleos N, Masters A, et al., 2026,
Highly Asymmetric Magnetosphere-Ionosphere-Thermosphere Coupling at Uranus
, Journal of Geophysical Research Space Physics, Vol: 131, ISSN: 2169-9380Magnetosphere-Ionosphere-Thermosphere (MIT) coupling is widely considered the dominant energy source responsible for maintaining the elevated thermospheric temperatures observed at the giant planets. At Uranus, the strongly tilted and asymmetric magnetic field produces a highly asymmetric magnetospheric configuration that may fundamentally alter the spatial distribution of energy deposition in the upper atmosphere. In this study, we investigate how Uranus' magnetic geometry influences thermospheric heating and circulation using a (Formula presented.) -D thermospheric circulation model updated to represent Uranus-like atmospheric conditions. The simulations show that magnetospheric forcing at the two magnetic poles produces markedly different thermospheric responses. At the magnetic south pole, where the magnetic field strength is larger and the pole lies close to the rotational pole, Joule heating produces a confined region of enhanced temperature resembling the polar hot spots observed at Jupiter and Saturn. In contrast, the magnetic north pole lies near the rotational equator and is associated with weaker magnetic field strengths and, therefore, higher ionospheric conductivities. Under these conditions, the imposed electric field drives heating across both hemispheres simultaneously, producing a much broader region of thermospheric heating that actually decreases near the rotational poles. These results demonstrate that Uranus' unusual magnetic geometry leads to a strongly asymmetric pattern of MIT-driven heating that differs significantly from Jupiter and Saturn. Comparing these results to recent JWST observations, which show relatively uniform thermospheric temperatures, we hypothesize that highly efficient meridional transport from the magnetic north pole may redistribute this energy globally, potentially explaining these observations.
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Journal articleDavies EE, Weiler E, Möstl C, et al., 2026,
Real-Time Prediction of Two Geomagnetic Storms Using Solar Orbiter as a Far Upstream Solar Wind Monitor
, Space Weather, Vol: 24We present the first real-time predictions of coronal mass ejection (CME) magnetic structure and resulting geomagnetic impact at Earth for two events using far-upstream observations from Solar Orbiter during March 2024. While our approach assumes idealized conditions for CME propagation and scaling, in situ magnetic field data from upstream monitors still produced realistic predictions despite the large heliocentric distance between Solar Orbiter and L1 (0.53 and 0.60 au). Geomagnetic index predictions were made 15.3 and 4.3 hr before the CME shock arrival at L1, and 33.9 and 10.3 hr ahead of peak storm time; a large improvement over current L1-based nowcasting capabilities. We find that observationally constraining the simple drag-based models using the upstream in situ observations improved arrival time estimates for the two events in this study, although arrival time errors of several hours still remain. Our results show that good predictions of CME magnetic structure and geomagnetic indices with actionable lead-times can be made with far upstream spacecraft, even with longitudinal separations up to 10 (Formula presented.) from the Sun-Earth line, over heliocentric distance ranges where radial evolution effects dominate over longitudinal effects. Limitations include different expansion behaviors for individual CMEs and regions within. Future missions providing continuous data, including solar wind plasma parameters alongside magnetic field measurements, could account for preexisting disturbed conditions and improve geomagnetic prediction accuracy. Our findings demonstrate the substantial value of real-time upstream solar wind measurements for enhancing geomagnetic forecasting accuracy at Earth and provide critical validation for future dedicated upstream space weather missions.
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Journal articleMallet A, Shi C, Tenerani A, et al., 2026,
Evolution and Impact of Switchbacks Throughout the Heliosphere
, Space Science Reviews, Vol: 222, ISSN: 0038-6308Magnetic switchbacks are large-amplitude fluctuations in the interplanetary magnetic field, and appear frequently in the near-Sun solar wind explored recently by Parker Solar Probe: these new observations have prompted many new studies into their properties and origins. Here, we first review what is known about how switchbacks evolve as they travel away from the Sun: both in terms of their expansion-driven growth and their decay due to various processes like turbulence, reconnection, dispersion, parametric instability, and interaction with interplanetary shocks. We then review the current state of knowledge on how switchbacks impact the physics of the solar wind as a whole: in terms of the turbulent cascade, acceleration and heating of the wind, modification of the open solar flux and scattering of energetic particles. Finally, we suggest future studies to further our understanding of switchback evolution and impacts on the heliosphere.
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Journal articleMarjani S, Mehrdad S, Quaas J, 2026,
Investigating the development of persistent contrails in ice supersaturated regions with cloudy backgrounds using ICON-LEM
, Atmospheric Chemistry and Physics, Vol: 26, Pages: 10695-10725, ISSN: 1680-7316Persistent contrails are a major contributor to aviation-induced non-CO<inf>2</inf> climate forcing, yet the extent to which their development depends on background cloud properties remains unclear. In this study, we aim to investigate persistent contrail development in various cloudy backgrounds. We use the high-resolution ICON-LEM model with a horizontal resolution of 154 m. Eight distinct ice-cloud scenarios are simulated as control runs, each initialized with realistic meteorological forcing. For each control case, a corresponding perturbation run is conducted by introducing an identical contrail, allowing us to assess its evolution within the same cloudy, ice-supersaturated environment. We find that persistent contrails embedded within natural cirrus clouds not only survive but can also alter the humidity field, cloud microphysics, and potentially the radiative properties of the host cloud. The evolution of persistent contrails is highly sensitive to the microphysical and thermodynamic properties of the background ice-supersaturated regions, particularly the combination of supersaturated layer thickness below flight level and the temporal availability of excess water vapor, as the former alone is not sufficient to sustain contrail development. Although vertical growth through fall streaks is commonly expected, we suggest that in regions of high ice supersaturation and low atmospheric stability, contrails may also expand above the flight height due to latent heat release from deposition. Our findings indicate that threshold criteria alone are insufficient to predict the growth and climate relevance of persistent contrails, because time-varying background cloud and humidity conditions strongly influence how far contrails develop.
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Journal articleEastwood J, Archer M, Waters C, et al., 2026,
RadCube MAGIC observations of complex field aligned currents associated with a supersubstorm during the May 2024 geomagnetic storm
, Scientific Reports, ISSN: 2045-2322Geomagnetic storms are a key driver of space weather impacts. The enhancement of ionospheric currents during these events can produce geomagnetically induced currents (GICs) that may interfere with the operation of ground infrastructure such as power grids, pipelines, and railway networks. It is therefore critical to understand how, why, and when very intense GICs may occur during an extended geomagnetic storm interval. Supersubstorms are extremely intense substorms which may occur during the main or recovery phases of geomagnetic storms. These rare events bear special investigation because they may have a significant impact on GIC formation during extreme geomagnetic storms. Multiple supersubstorms were observed during the May 2024 geomagnetic storm, and here we report new observations of supersubstorm field aligned currents (FACs), observed in situ by the MAGnetometer from Imperial College (MAGIC) instrument on the RadCube technology demonstration CubeSat. These measurements provide new insight into the detailed structure of supersubstorm FACs, complementing global FAC maps, and reveal an extended spatial region containing magnetic fluctuations across a broad range of spatial/temporal scales, including intense localised current spikes. As well as revealing new details about supersubstorm-related FACs, these observations illustrate the need for dense constellations of low-Earth-orbit satellite-based magnetometers for space weather monitoring.
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Journal articleDakeyo JB, Ervin T, Bale S, et al., 2026,
On the Radial Evolution of the Solar Wind: The Source Alignment Method Applied to Parker Solar Probe and Solar Orbiter Observations
, Astrophysical Journal, Vol: 1006, ISSN: 0004-637XThe properties of the solar wind, as measured in situ throughout the heliosphere, depend both on the characteristics of its coronal source and on the intrinsic processes governing its interplanetary evolution. Recently, radial and Parker spiral alignment techniques have been applied to Parker Solar Probe (PSP) and Solar Orbiter (SO) observations to investigate the radial evolution of the same solar wind parcel. These studies have shown that the solar wind can undergo significant acceleration even beyond its primary acceleration region (i.e., above 15 R<inf>⊙</inf>). However, such radial and Parker spiral alignments are rare in practice, which limits the statistical significance and general applicability of the results. We introduce a new source alignment technique designed to overcome these limitations. Using magnetic backmapping, we associate similar solar wind streams observed by the two spacecraft based on the proximity of their photospheric footpoints, combined with additional in situ stream similarity criteria. Applying the source alignment method to PSP and SO observations, we identify a total of 548 alignment intervals, each lasting 30 minutes. By constructing statistics over all alignments, we find that the solar wind speed increases by an average of 45% per radial decade (approximately 147 km s<sup>−1</sup>) between the two probes. This result demonstrates that solar wind acceleration in the inner heliosphere remains significant compared to that occurring below 15 R<inf>⊙</inf>. Among the different studied plasma parameters, the radial evolution of the electron temperature and plasma density shows the strongest anticorrelation with the increase in bulk velocity.
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Journal articleManolis AA, Manolis TA, Vouliotis A, et al., 2026,
Pericarditis/Myopericarditis/Pericardial Effusion: A Contemporary Approach to Diagnosis and Management.
, Curr Vasc PharmacolPericarditis is a common disease caused by various factors such as viral infections, systemic diseases, or drugs. A diagnosis of pericarditis is rendered in up to 5% of Emergency Room (ER) visits for non-ischemic chest pain. It is diagnosed when pleuritic chest pain is present, accentuated in the supine position, accompanied by ECG changes comprising new extensive ST-segment elevation and PR depression, a pericardial friction rub, and new or increased pericardial effusion on echocardiography. In North America and Western Europe, the most common causes of acute pericarditis are idiopathic or viral, followed by post-procedural (iatrogenic) pericarditis, radiation therapy, and cardiac surgery. Tuberculosis is the most common cause of pericarditis in endemic areas and is managed with antituberculosis therapy, with corticosteroids used when there is concurrent constrictive pericarditis. New diagnostic techniques have aided the sampling and analysis of pericardial fluid and in determining its cause. Treatment of pericarditis comprises high-dose Non-Steroidal AntiInflammatory Drugs (NSAIDs) for uncomplicated cases, with doses tapered when symptoms have subsided and C-reactive protein level has normalized, typically over several weeks. Colchicine (often a 3-6-month course) is needed to both alleviate symptoms and decrease recurrences, while glucocorticoids and newer therapies with interleukin-1 blockers are reserved for recurrences and/or failures of prior therapies. Integrated use of new imaging methods facilitates more precise detection and better management of complications such as pericardial effusion or constriction. The diagnostic yield of extensive laboratory evaluation and pericardiocentesis remains low; hence, invasive procedures should be limited mostly to patients in whom a therapeutic intervention is needed. The majority of pericardial effusions can be safely drained with an echo-guided percutaneous technique. Pericardiectomy remains the definitive treatment for
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Journal articlePugsley G, Gryspeerdt E, Nair V, 2026,
Reply to Yu et al.: Meteorological covariations do not reproduce diurnal cloud fraction response to aerosol.
, Proc Natl Acad Sci U S A, Vol: 123 -
Journal articleBurne S, Boscoboinik G, Bertucci C, et al., 2026,
Correlated response of the Martian dayside magnetic pileup boundary and bow shock to solar wind and planetary drivers
, The Astrophysical Journal, Vol: 1005, ISSN: 0004-637XThe interaction between the supermagnetosonic solar wind and the atmosphere of the weakly magnetized planet Mars forms an induced magnetosphere preceded by a magnetic pileup boundary (MPB) and bow shock (BS). In situ measurements have shown that these boundaries are permanent and well-defined structures that exhibit significant variability driven by external (Sun, solar wind) and internal (planetary) factors. In this work, we used MAVEN observations from 2014 to 2019 to analyze the coupled behavior of the BS and MPB, focusing on their spatial correlation and variability under varying conditions. We examine contiguous BS-MPB spacecraft crossings and the magnetosheath region between them, and we explore the effects of various plasma parameters on the relative position of the boundaries and the thickness of the magnetosheath. We demonstrate a statistical correlation between the BS and MPB positions across multiple timescales, including sustained local solar wind and planetary conditions, seasonal changes, and solar cycle variations. These results support the interpretation that the MPB plays a key role as an electromagnetic obstacle to the solar wind, effectively controlling the formation of the bow shock. We also confirm the limited size of the Martian magnetosheath, both in absolute terms and relative to fundamental plasma scales, which has important implications for understanding the microscopic plasma processes responsible for solar wind thermalization. While acknowledging the limitations of single-spacecraft measurements, this study provides a foundation for future multipoint probing of the Martian environment and the magnetosphere as a system.
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Journal articleHartinger MD, Shi X, Verkhoglyadova O, et al., 2026,
Statistical analysis of Pc3‐5 total electron content disturbances at mid‐Latitudes: comparison to the auroral zone
, Journal of Geophysical Research: Space Physics, Vol: 131, ISSN: 2169-9380<jats:title>Abstract</jats:title> <jats:p> Ionospheric Total Electron Content disturbances (dTEC) in the Ultra Low Frequency (ULF, timescales 10 min) range can be driven from below by processes at Earth's surface and lower atmosphere and from above by magnetospheric processes. Using magnetospheric satellite magnetometer, ground‐based magnetometer, and dTEC measurements in the auroral zone, Hartinger et al. (2025), <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2024ja033456">https://doi.org/10.1029/2024ja033456</jats:ext-link> showed that over much of the Pc3‐5 band (∼2–50 mHz) ULF waves routinely drive dTEC perturbations correlated with magnetic field disturbances (dBground), suggesting dTEC could be used as a ULF wave diagnostic. Motivated by the significant differences expected for magnetosphere, ionosphere, atmosphere, and ground properties at a different latitude, we extend Hartinger et al. (2025), <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2024ja033456">https://doi.org/10.1029/2024ja033456</jats:ext-link> to examine mid‐latitude ( degrees magnetic latitude) dTEC during conjunctions with the Van Allen Probes satellites, a ground magnetometer, and a Global Navigation Satellite System receiver. Consistent with the auroral zone, we find that dTEC often has a corresponding dBground signature, and that dTEC and dBground are well correlated with results dependent on the component of the magnetic field. We also find that dTEC amplitudes are lower (0.5 TECU) and tend to occur at higher frequencies than in the auroral zone, as expected for magnetospheric Pc3‐5 wave latitude dependence. In contrast to the auroral zone, we find that dTEC power does not have
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Journal articleDasgupta B, Pandey S, Houweling S, et al., 2026,
Global methane emission estimates from a dual-isotope inversion: new constraints from <i>δ</i> D-CH <sub>4</sub>
, Atmospheric Chemistry and Physics, Vol: 26, Pages: 8601-8616<jats:p>Abstract. Methane (CH4) is a potent greenhouse gas; however, the causes of its growth since 2006 are a subject of debate. While measurements of CH4 mole fraction and carbon isotopic composition (δ13C-CH4) have been extensively used to investigate the global CH4 budget, the hydrogen isotopic composition (δD-CH4) remains underutilised despite its unique sensitivity to source types and oxidation processes. Here, we assimilate a newly harmonised 35-year dataset of dual isotope measurements from high-latitude monitoring stations in both hemispheres within a two-box Bayesian inversion to quantify global CH4 sources and sinks. The model integrates prior emissions from five source categories based on global bottom-up inventories. Methane removal processes are represented by sink-specific kinetic isotope effects as tropospheric and stratospheric loss, and soil uptake. We find that the inclusion of δD-CH4 improves the model's ability to constrain emission apportionment between biogenic and thermogenic sources, particularly for fossil fuel emissions during the late 1990s and early 2000s, which affects CH4 lifetime estimate. CH4 increase post-2006 is driven mainly by rising wetland emissions, while fossil-fuel growth is modest, biomass burning declines, and agriculture and waste make smaller, regionalised contributions. The optimised inversion results favour a strong 13C kinetic isotope effect in total tropospheric CH4 removal and a net shortening of the NH lifetime of CH4 by 0.2 years. This study demonstrates the added value of incorporating δD-CH4 into inverse modelling frameworks and underscores the importance of long-term δD-CH4 measurements for advancing our understanding of CH4 biogeochemistry and its role in the global carbon cycle.</jats:p>
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Journal articleTeixeira JCM, Burton C, Kelley DI, et al., 2026,
Assessing the impact of the Human Development Index on historical trends in the INFERNO fire model
, Earth System Dynamics, Vol: 17, Pages: 739-767, ISSN: 2190-4979Fire schemes within Earth System Models capture long-term historical trends in burnt area, but they struggle to reproduce the pronounced decline observed over the past two decades. This study investigates whether the observed decline in global burnt area during 1998–2016 can be better represented in the JULES-INFERNO fire model by introducing a globally uniform dependence on the Human Development Index (HDI) as a proxy for socio-economic fire controls. This approach substantially reduces regional biases in annual burned area. In Temperate North America, model bias decreases from +735.57 % to +44.46 %, with similarly large reductions in Central America, Southern Hemisphere South America, Europe, and the Middle East. HDI also improves the representation of burned area trends in eight of the 14 GFED4s regions with significant negative trends in observations. However, correcting large positive regional biases removes compensating errors in the original model, leading to a stronger global negative bias, which shifts from −34.35 Mha in JULES-INFERNO to approximately −111 Mha in JULES-INFERNO with the HDI implementation. Overall, while HDI improves regional performance and better captures observed downward trends in some regions, it also reduces interannual variability and underestimates larger fires. This highlights both the potential and limitations of representing socio-economic influences within fire models using a simplified globally uniform formulation.
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Journal articleManolis AS, Manolis AA, Manolis TA, et al., 2026,
Occupational and Environment-Related Cardiovascular Disease: A Comprehensive Review of the Literature.
, Curr Vasc PharmacolWork is a social determinant of Cardiovascular (CV) and general health and can both influence and be influenced by health. The type of work, working conditions, and work environment are fundamental social determinants of CV and general health status. Climate change presents an urgent and increasing threat to workers' health, via both direct exposure to environmental risks and the indirect worsening of social and health inequalities. Occupational health, which focuses on the promotion of mental and physical health and well-being of workers, and the avoidance of occupationrelated health risks, is a crucial but less discussed concern and component of human health. Relevant research at the intersection of climate change and occupational health remains scarce. Additionally, mitigation of climate change and adaptation efforts are driving forces for rapid transformations in the workplace, including shifts towards sustainability and circular economy models. These transitions are creating new occupational hazards, including those concerning renewable energy and the circular economy sectors. Investment in occupational health research and surveillance should be increased to address the evolving influences of both climate change and the green transition, to enhance and protect workers' CV and general health. Among the work-related factors that play an important role in patients with CVD, the following seem crucial: work participation, physical and mental work capability, appropriate work, support from and flexibility of the work environment, inter-personal communication, person-centered milieu, and interdisciplinary communication. A moderate leisure-time physical activity combined with moderate occupational physical activity may be a more plausible way to combine these two activities to sustain and/or improve CV health. Such an approach may be able to ameliorate workrelated outcomes in patients with CVD. Finally, lifestyle interventions targeting multiple behaviors are also mos
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Journal articleDong Y, Lu K, Hwang Y-T, et al., 2026,
Tropical impacts of the Southern Ocean underestimated by mean-state biases.
, Sci Adv, Vol: 12Observed sea-surface temperature (SST) trends over recent decades feature cooling in the tropical eastern Pacific and the Southern Ocean (SO). Growing evidence suggests that tropical cooling may partly stem from remote impacts of the SO. Using a hierarchy of multimodel simulations, we demonstrate that these teleconnections are robustly modulated by the mean-state intertropical convergence zone (ITCZ): Models with a more realistic ITCZ simulate a stronger tropical SST response to SO forcing via stronger wind-evaporation-SST feedback. When realistic Antarctic meltwater forcing is included, correcting a model's tropical mean-state bias yields a stronger tropical cooling response to meltwater-driven SO cooling, improving the agreement between simulated and observed SST trends. Our results suggest that the SO's contribution to tropical warming patterns is systematically underestimated due to model mean-state biases. Improving representations of the mean-state climate is therefore critical for accurately assessing large-scale climate responses associated with historical and future warming patterns.
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Journal articleSun W, Phan T, Huang J, et al., 2026,
Parker Solar Probe Observations of Compound Reconnection Exhaust Boundaries and Mirror-mode Structures in the near-Sun Heliospheric Current Sheet
, Astrophysical Journal Letters, Vol: 1003, ISSN: 2041-8205Magnetic reconnection is a fundamental physical process that can drive rapid conversion of magnetic energy into plasma bulk flows, thermal heating, and particle acceleration in space and astrophysical plasmas. Classical reconnection theory predicts that the Alfvénic reconnection exhausts are bounded by pairs of slow-mode shocks. However, identifying and characterizing these shocks through in situ spacecraft observations remains a challenge. Here, we report Parker Solar Probe observations of a reconnection exhaust embedded in the heliospheric current sheet at a heliocentric distance of 12.2 (Formula presented) R⨀. The reconnection exhaust is bounded on both boundaries by compound magnetic structures rather than a pair of pure slow shocks. Each boundary consists of a rapidly evolving, steep, inner slow shock, whose Mach numbers and shock-normal angles change significantly within several minutes, and an outer, gradual compound structure that comprises a slow shock and a rotational discontinuity. These slow shocks are quasi-perpendicular and are accompanied by enhanced proton perpendicular heating. Deep within the reconnection exhaust, high perpendicular temperature together with large plasma (Formula presented) β trigger mirror instability and generate mirror-mode structures. These observations provide new insights into the structure of reconnection exhaust boundaries and their role in energy conversion in the near-Sun plasma.
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Journal articleWyper PF, Squire J, Pariat E, et al., 2026,
Magnetic Switchback Formation: A Review of Proposed Mechanisms
, Space Science Reviews, Vol: 222, ISSN: 0038-6308Magnetic switchbacks are large amplitude deflections of the magnetic field within the solar wind. They are Alfvénic in character and so are associated with a spike in velocity and a generally small variation in local plasma density. Early orbits of Parker Solar Probe revealed that the solar wind near the Sun is dominated by these structures, and therefore, they may be playing an important role in the energy budget and acceleration of the young solar wind. In this review, we present an overview of different mechanisms that have been proposed for how switchbacks could be formed. We group the mechanisms by whether they predominantly act in the low solar atmosphere or within the solar wind (in situ). We focus on mechanisms that can create reversals of the ambient magnetic field direction and, thus, account for the most extreme perturbations. The general consensus is that mechanisms in the lower solar atmosphere do not form such reversals on their own but provide the seed perturbations, flows, or particle beams necessary for in situ mechanisms to create switchbacks within the solar wind. Switchback observations thus likely contain an imprint of the coronal source of the seed perturbation or flow, which is evolved further locally by one of several plausible in situ mechanisms. We discuss the strengths and weaknesses of each mechanism and outline future observational and theoretical tests that could help differentiate between them.
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Journal articleCanu P, Bouzid V, Piberne R, et al., 2026,
STAFF instrument calibration, sensitivity, and performance evolutions during the cluster mission
, Journal of Geophysical Research: Space Physics, Vol: 131, ISSN: 2169-9380The Spatio-Temporal Analysis of Field Fluctuations(STAFF) instruments onboard the Cluster satellites were designed to measure magnetic fluctuations in the 0.2–12 Hz and 0.2–180 Hz frequency ranges from the Search-Coil Magnetometer (SCM), as well as electromagnetic spectra from the Spectrum Analyzer (SA) in the 8–4000 Hz range. They provided a considerable amount of data throughout the 24-year mission. The production and calibration of these datasets were detailed in Robert et al. (2014), which demonstrated its excellent quality and good agreement with the FluxGate Magnetometer (FGM) measurements over their commonfrequency range. The Cluster's 24 years of operation, which far exceed the nominal two-year mission, represent the longest flight of search coil magnetometers and offer a unique opportunity to evaluate their performance over such a long period, as well as to compare the results of four initially identical instruments. The present work, based on data now archived at the Cluster Scientific Archive (CSA), examines the evolution of these products after the first 11 years in space, and until the end of the Cluster operations in September 2024. The quality of the measurements, calibration, sensitivities, and their agreement between spacecraft proved to be excellent and remained stable throughout the mission. Comparison of spectra derived from the calibrated waveforms of STAFF (CWF) and FGM shows a very good agreement until the end of operations, a further proof of the high quality of their respective calibrations.
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