Search or filter publications

Filter by type:

Filter by publication type

Filter by year:

to

Results

  • Showing results for:
  • Reset all filters

Search results

  • Journal article
    Wilson L, Goodrich K, Turner D, Cohen I, Whittlesey P, Schwartz Set al., 2023,

    The necessity of accurate measurements of thermal velocity distribution functions in the solar wind

    , Vol. 55, Issue 3 (Heliophysics 2024 Decadal Whitepapers)
  • Journal article
    Arridge CS, Xystouris G, Cochrane C, Cohen I, DiBraccio G, Kollmann P, Lamy L, Masters A, Paty C, Solomonidou A, Stallard T, Styczinski M, Sulaiman Aet al., 2023,

    Fundamental Space Physics in Uranus’ Magnetosphere

    , Vol. 55, Issue 3 (Heliophysics 2024 Decadal Whitepapers)
  • Journal article
    Montgomery J, Ebert R, Allegrini F, Bagenal F, Bolton S, DiBraccio G, Fuselier S, Wilson R, Masters Aet al., 2023,

    Investigating the occurrence of Kelvin-Helmholtz instabilities at Jupiter’s dawn magnetopause

    , Geophysical Research Letters, Vol: 50, ISSN: 0094-8276

    We use the Kelvin-Helmholtz instability (KHI) condition with particle and magnetic field observations from Jovian Auroral Distributions Experiment and MAG on Juno along the dawn flank of Jupiter's magnetosphere. We identify the occurrence of magnetopause crossings that show evidence of being KH (Kelvin-Helmholtz) unstable. When estimating the k vector to be parallel to the velocity shear, we find that 25 of 62 (40%) magnetopause crossings satisfy the KHI condition. When considering the k vector of the maximum growth rate through a solid angle approach, we find that 60 of 62 (97%) events are KH unstable. This study shows evidence of KH waves at Jupiter's dawn flank, including primary drivers such as high velocity shears and changes in plasma pressure. Signatures of magnetic reconnection were also observed in ∼25% of the KH unstable crossings. We discuss these results and their implication for the prevalence of KHI at Juno's dawn magnetopause as measured by Juno.

  • Journal article
    Kang SM, Yu Y, Deser C, Zhang X, Kang I-S, Lee S-S, Rodgers KB, Ceppi Pet al., 2023,

    Global impacts of recent Southern Ocean cooling

    , Proceedings of the National Academy of Sciences, Vol: 120, Pages: 1-10, ISSN: 0027-8424

    Since the beginning of the satellite era, Southern Ocean sea surface temperatures (SSTs) have cooled, despite global warming. While observed Southern Ocean cooling has previously been reported to have minimal impact on the tropical Pacific, the efficiency of this teleconnection has recently shown to be mediated by subtropical cloud feedbacks that are highly model-dependent. Here, we conduct a coupled model intercomparison of paired ensemble simulations under historical radiative forcing: one with freely evolving SSTs and the other with Southern Ocean SST anomalies constrained to follow observations. We reveal a global impact of observed Southern Ocean cooling in the model with stronger (and more realistic) cloud feedbacks, including Antarctic sea–ice expansion, southeastern tropical Pacific cooling, northward-shifted Hadley circulation, Aleutian low weakening, and North Pacific warming. Our results therefore suggest that observed Southern Ocean SST decrease might have contributed to cooler conditions in the eastern tropical Pacific in recent decades.

  • Journal article
    Khabarova O, Balasis G, Bučík R, Eastwood JP, Erickson PJ, Treumann RAet al., 2023,

    Editorial: Reviews in space physics

    , Frontiers in Astronomy and Space Sciences, Vol: 10, Pages: 1-3, ISSN: 2296-987X
  • Journal article
    Suen GHH, Owen CJ, Verscharen D, Horbury TS, Louarn P, De Marco Ret al., 2023,

    Magnetic reconnection as an erosion mechanism for magnetic switchbacks

    , ASTRONOMY & ASTROPHYSICS, Vol: 675, ISSN: 0004-6361
  • Journal article
    Yardley SL, Owen CJ, Long DM, Baker D, Brooks DH, Polito V, Green LM, Matthews S, Owens M, Lockwood M, Stansby D, James AW, Valori G, Giunta A, Janvier M, Ngampoopun N, Mihailescu T, To ASH, van Driel-Gesztelyi L, Demoulin P, D'Amicis R, French RJ, Suen GHH, Rouillard AP, Pinto RF, Reville V, Watson CJ, Walsh AP, De Groof A, Williams DR, Zouganelis I, Mueller D, Berghmans D, Auchere F, Harra L, Schuehle U, Barczynski K, Buchlin E, Cuadrado RA, Kraaikamp E, Mandal S, Parenti S, Peter H, Rodriguez L, Schwanitz C, Smith P, Teriaca L, Verbeeck C, Zhukov AN, De Pontieu B, Horbury T, Solanki SK, Iniesta JCDT, Woch J, Gandorfer A, Hirzberger J, Suarez DO, Appourchaux T, Calchetti D, Sinjan J, Kahil F, Albert K, Volkmer R, Carlsson M, Fludra A, Hassler D, Caldwell M, Fredvik T, Grundy T, Guest S, Haberreiter M, Leeks S, Pelouze G, Plowman J, Schmutz W, Sidher S, Thompson WT, Louarn P, Federov Aet al., 2023,

    Slow Solar Wind Connection Science during Solar Orbiter's First Close Perihelion Passage

    , ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 267, ISSN: 0067-0049
  • Journal article
    Halekas JS, Bale SD, Berthomier M, Chandran BDG, Drake JF, Kasper JC, Klein KG, Larson DE, Livi R, Pulupa MP, Stevens ML, Verniero JL, Whittlesey Pet al., 2023,

    Quantifying the Energy Budget in the Solar Wind from 13.3 to 100 Solar Radii

    , ASTROPHYSICAL JOURNAL, Vol: 952, ISSN: 0004-637X
  • Journal article
    Huang J, Kasper JC, Fisk LA, Larson DE, McManus MD, Chen CHK, Martinovic MM, Klein KG, Thomas L, Liu M, Maruca BA, Zhao L, Chen Y, Hu Q, Jian LK, Verniero JL, Velli M, Livi R, Whittlesey P, Rahmati A, Romeo O, Niembro T, Paulson K, Stevens M, Case AW, Pulupa M, Bale SD, Halekas JSet al., 2023,

    The Structure and Origin of Switchbacks: Parker Solar Probe Observations

    , ASTROPHYSICAL JOURNAL, Vol: 952, ISSN: 0004-637X
  • Journal article
    Liu W, Zhao J, Wang T, Dong X, Kasper JC, Bale SD, Shi C, Wu Det al., 2023,

    The Radial Distribution of Ion-scale Waves in the Inner Heliosphere

    , ASTROPHYSICAL JOURNAL, Vol: 951, ISSN: 0004-637X
  • Journal article
    Sioulas N, Velli M, Huang Z, Shi C, Bowen TAA, Chandran BDG, Liodis I, Davis N, Bale SDD, Horbury TS, de Wit TD, Larson D, Stevens MLL, Kasper J, Owen CJJ, Case A, Pulupa M, Malaspina DMM, Livi R, Goetz K, Harvey PRR, MacDowall RJJ, Bonnell JWWet al., 2023,

    On the Evolution of the Anisotropic Scaling of Magnetohydrodynamic Turbulence in the Inner Heliosphere

    , ASTROPHYSICAL JOURNAL, Vol: 951, ISSN: 0004-637X
  • Journal article
    Leblanc F, Roth L, Chaufray JY, Modolo R, Galand M, Ivchenko N, Carnielli G, Baskevitch C, Oza A, Werner ALEet al., 2023,

    Ganymede's atmosphere as constrained by HST/STIS observations

    , Icarus, Vol: 399, ISSN: 0019-1035

    A new analysis of aurora observations of Ganymede's atmosphere on the orbital leading and trailing hemispheres has been recently published by Roth et al. (2021), suggesting that water is its main constituent near noon. Here, we present two additional aurora observations of Ganymede's sub-Jovian and anti-Jovian hemispheres, which suggest a modulation of the atmospheric H2O/O2 ratio on the moon's orbital period, and analyze the orbital evolution of the atmosphere. For this, we propose a reconstruction of aurora observations based on a physical modelling of the exosphere taking into account its orbital variability (the Exospheric Global Model; Leblanc et al., 2017). The solution described in this paper agrees with Roth et al. (2021) that Ganymede's exosphere should be dominantly composed of water molecules. From Ganymede's position when its leading hemisphere is illuminated to when it is its trailing hemisphere, the column density of O2 may vary between 4.3 × 1014 and 3.6 × 1014 cm−2 whereas the H2O column density should vary between 5.6 × 1014 and 1.3 × 1015 cm−2. The water content of Ganymede's atmosphere is essentially constrained by its sublimation rate whereas the O2 component of Ganymede's atmosphere is controlled by the radiolytic yield. The other species, products of the water molecules, vary in a more complex way depending on their sources, either as ejecta from the surface and/or as product of the dissociation of the other atmospheric constituents. Electron impact on H2O and H2 molecules is shown to likely produce H Lyman-alpha emissions close to Ganymede, in addition to the observed extended Lyman-alpha corona from H resonant scattering. All these conclusions being highly dependent on our capability to accurately model the origins of the observed Ganymede auroral emissions, modelling these emissions remains poorly constrained without an accurate knowledge of the Jovian magnetospheric and Ganymede ionospheric electron popul

  • Journal article
    Duan D, He J, Zhu X, Zhuo R, Wu Z, Nicolaou G, Huang J, Verscharen D, Yang L, Owen CJ, Fedorov A, Louarn P, Horbury TSet al., 2023,

    Kinetic Features of Alpha Particles in a Pestchek-like Magnetic Reconnection Event in the Solar Wind Observed by Solar Orbiter

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 952, ISSN: 2041-8205
  • Journal article
    Nowack P, Ceppi P, Davis SM, Chiodo G, Ball W, Diallo MA, Hassler B, Jia Y, Keeble J, Joshi Met al., 2023,

    Response of stratospheric water vapour to warming constrained by satellite observations

    , Nature Geoscience, Vol: 16, Pages: 577-583, ISSN: 1752-0894

    <jats:title>Abstract</jats:title><jats:p>Future increases in stratospheric water vapour risk amplifying climate change and slowing down the recovery of the ozone layer. However, state-of-the-art climate models strongly disagree on the magnitude of these increases under global warming. Uncertainty primarily arises from the complex processes leading to dehydration of air during its tropical ascent into the stratosphere. Here we derive an observational constraint on this longstanding uncertainty. We use a statistical-learning approach to infer historical co-variations between the atmospheric temperature structure and tropical lower stratospheric water vapour concentrations. For climate models, we demonstrate that these historically constrained relationships are highly predictive of the water vapour response to increased atmospheric carbon dioxide. We obtain an observationally constrained range for stratospheric water vapour changes per degree of global warming of 0.31 ± 0.39 ppmv K<jats:sup>−1</jats:sup>. Across 61 climate models, we find that a large fraction of future model projections are inconsistent with observational evidence. In particular, frequently projected strong increases (&gt;1 ppmv K<jats:sup>−1</jats:sup>) are highly unlikely. Our constraint represents a 50% decrease in the 95th percentile of the climate model uncertainty distribution, which has implications for surface warming, ozone recovery and the tropospheric circulation response under climate change.</jats:p>

  • Journal article
    Milan SE, Mooney MK, Bower GE, Taylor MGGT, Paxton LJ, Dandouras I, Fazakerley AN, Carr CM, Anderson BJ, Vines SKet al., 2023,

    The association of cusp‐Aligned arcs with plasma in the magnetotail implies a closed magnetosphere

    , JGR: Space Physics, Vol: 128, Pages: 1-17, ISSN: 2169-9402

    We investigate a 15-day period in October 2011. Auroral observations by the Special Sensor Ultraviolet Spectrographic Imager instrument onboard the Defense Meteorological Satellite Program F16, F17, and F18 spacecraft indicate that the polar regions were covered by weak cusp-aligned arc (CAA) emissions whenever the interplanetary magnetic field (IMF) clock angle was small, |θ| < 45°, which amounted to 30% of the time. Simultaneous observations of ions and electrons in the tail by the Cluster C4 and Geotail spacecraft showed that during these intervals dense (≈1 cm−3) plasma was observed, even as far from the equatorial plane of the tail as |ZGSE| ≈ 13 RE. The ions had a pitch angle distribution peaking parallel and antiparallel to the magnetic field and the electrons had pitch angles that peaked perpendicular to the field. We interpret the counter-streaming ions and double loss-cone electrons as evidence that the plasma was trapped on closed field lines, and acted as a source for the CAA emission across the polar regions. This suggests that the magnetosphere was almost entirely closed during these periods. We further argue that the closure occurred as a consequence of dual-lobe reconnection. Our finding forces a significant re-evaluation of the magnetic topology of the magnetosphere during periods of northwards IMF.

  • Journal article
    Williams RG, Ceppi P, Roussenov V, Katavouta A, Meijers AJSet al., 2023,

    The role of the Southern Ocean in the global climate response to carbon emissions

    , Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol: 381, ISSN: 1364-503X

    <jats:p>The effect of the Southern Ocean on global climate change is assessed using Earth system model projections following an idealized 1% annual rise in atmospheric CO<jats:sub>2</jats:sub>. For this scenario, the Southern Ocean plays a significant role in sequestering heat and anthropogenic carbon, accounting for 40% ± 5% of heat uptake and 44% ± 2% of anthropogenic carbon uptake over the global ocean (with the Southern Ocean defined as south of 36°S). This Southern Ocean fraction of global heat uptake is however less than in historical scenarios with marked hemispheric contrasts in radiative forcing. For this idealized scenario, inter-model differences in global and Southern Ocean heat uptake are strongly affected by physical feedbacks, especially cloud feedbacks over the globe and surface albedo feedbacks from sea-ice loss in high latitudes, through the top-of-the-atmosphere energy balance. The ocean carbon response is similar in most models with carbon storage increasing from rising atmospheric CO<jats:sub>2</jats:sub>, but weakly decreasing from climate change with competing ventilation and biological contributions over the Southern Ocean. The Southern Ocean affects a global climate metric, the transient climate response to emissions, accounting for 28% of its thermal contribution through its physical climate feedbacks and heat uptake, and so affects inter-model differences in meeting warming targets.</jats:p><jats:p>This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.</jats:p>

  • Journal article
    Desai R, Zhang Z, 2023,

    Simulating secondary electron and ion emission from the Cassini spacecraft in Saturn's ionosphere

    , The Planetary Science Journal, Vol: 4, ISSN: 2632-3338

    The Cassini spacecraft's Grand Finale flybys through Saturn's ionosphere provided unprecedented insight into the composition and dynamics of the gas giant's upper atmosphere and a novel and complex spacecraft-plasma interaction. In this article, we further study Cassini's interaction with Saturn's ionosphere using three dimensional Particle-in-Cell simulations. We focus on understanding how electrons and ions, emitted from spacecraft surfaces due to the high-velocity impact of atmospheric water molecules, could have affected the spacecraft potential and low-energy plasma measurements. The simulations show emitted electrons extend upstream along the magnetic field and, for sufficiently high emission rates, charge the spacecraft to positive potentials. The lack of accurate emission rates and characteristics, however, makes differentiation between the prominence of secondary electron emission and ionospheric charged dust populations, which induce similar charging effects, difficult for Cassini. These results provide further context for Cassini's final measurements and highlight the need for future laboratory studies to support high-velocity flyby missions through planetary and cometary ionospheres.

  • Journal article
    Dresing N, Rodriguez-Garcia L, Jebaraj IC, Warmuth A, Wallace S, Balmaceda L, Podladchikova T, Strauss RD, Kouloumvakos A, Palmroos C, Krupar V, Gieseler J, Xu Z, Mitchell JG, Cohen CMS, de Nolfo GA, Palmerio E, Carcaboso F, Kilpua EKJ, Trotta D, Auster U, Asvestari E, da Silva D, Droge W, Getachew T, Gomez-Herrero R, Grande M, Heyner D, Holmstroem M, Huovelin J, Kartavykh Y, Laurenza M, Lee CO, Mason G, Maksimovic M, Mieth J, Murakami G, Oleynik P, Pinto M, Pulupa M, Richter I, Rodriguez-Pacheco J, Sanchez-Cano B, Schuller F, Ueno H, Vainio R, Vecchio A, Veronig AM, Wijsen Net al., 2023,

    The 17 April 2021 widespread solar energetic particle event

    , ASTRONOMY & ASTROPHYSICS, Vol: 674, ISSN: 0004-6361
  • Journal article
    Bale SD, Drake JF, McManus MD, Desai MI, Badman ST, Larson DE, Swisdak M, Horbury TS, Raouafi NE, Phan T, Velli M, McComas DJ, Cohen CMS, Mitchell D, Panasenco O, Kasper JCet al., 2023,

    Interchange reconnection as the source of the fast solar wind within coronal holes

    , NATURE, Vol: 618, Pages: 252-+, ISSN: 0028-0836
  • Journal article
    Qi Y, Ergun R, Pathak N, Li TC, Eriksson S, Chasapis A, Schwartz SJ, Ahmadi N, Vo T, Newman D, Usanova M, Wilder FD, Shuster Jet al., 2023,

    The Nonorthogonal X-line in a Small Guide-field Reconnection Event in the Magnetotail

    , ASTROPHYSICAL JOURNAL, Vol: 950, ISSN: 0004-637X
  • Journal article
    Davis N, Chandran BDG, Bowen TA, Badman ST, de Wit TD, Chen CHK, Bale SD, Huang Z, Sioulas N, Velli Met al., 2023,

    The Evolution of the 1/<i>f</i> Range within a Single Fast-solar-wind Stream between 17.4 and 45.7 Solar Radii

    , ASTROPHYSICAL JOURNAL, Vol: 950, ISSN: 0004-637X
  • Journal article
    Perri S, Prete G, Zimbardo G, Trotta D, Wilson III LB, Lario D, Servidio S, Valentini F, Giacalone Jet al., 2023,

    Interpretation of Flat Energy Spectra Upstream of Fast Interplanetary Shocks

    , ASTROPHYSICAL JOURNAL, Vol: 950, ISSN: 0004-637X
  • Journal article
    Baker D, Demoulin P, Yardley SL, Mihailescu T, van Driel-Gesztelyi L, D'Amicis R, Long DM, To ASH, Owen CJ, Horbury TS, Brooks DH, Perrone D, French RJ, James AW, Janvier M, Matthews S, Stangalini M, Valori G, Smith P, Cuadrado RA, Peter H, Schuehle U, Harra L, Barczynski K, Berghmans D, Zhukov AN, Rodriguez L, Verbeeck Cet al., 2023,

    Observational Evidence of S-web Source of the Slow Solar Wind

    , ASTROPHYSICAL JOURNAL, Vol: 950, ISSN: 0004-637X
  • Journal article
    Huang Z, Sioulas N, Shi C, Velli M, Bowen T, Davis N, Chandran BDG, Matteini L, Kang N, Shi X, Huang J, Bale SD, Kasper JC, Larson DE, Livi R, Whittlesey PL, Rahmati A, Paulson K, Stevens M, Case AW, de Wit TD, Malaspina DMM, Bonnell JW, Goetz K, Harvey PRR, MacDowall RJJet al., 2023,

    New Observations of Solar Wind 1/<i>f</i> Turbulence Spectrum from Parker Solar Probe

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 950, ISSN: 2041-8205
  • Journal article
    Hall RJ, Mitchell DM, Seviour WJM, Wright CJet al., 2023,

    Surface hazards in North-west Europe following sudden stratospheric warming events

    , ENVIRONMENTAL RESEARCH LETTERS, Vol: 18, ISSN: 1748-9326
  • Journal article
    Malaspina DMM, Toma A, Szalay JRR, Pulupa M, Pokorny P, Bale SDD, Goetz Ket al., 2023,

    A Dust Detection Database for the Inner Heliosphere Using the Parker Solar Probe Spacecraft

    , ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 266, ISSN: 0067-0049
  • Journal article
    de Moortel I, Eastwood J, Bridges J, Burchell M, Elseworth Y, Imber S, King A, Morton Ret al., 2023,

    Future UK solar system science

    , Astronomy and Geophysics, Vol: 64, Pages: 3.34-3.38, ISSN: 0035-8738
  • Journal article
    Mozer F, Bale S, Kellogg P, Romeo O, Vasko I, Verniero Jet al., 2023,

    Arguments for the physical nature of the triggered ion-acoustic waves observed on the Parker Solar Probe

    , PHYSICS OF PLASMAS, Vol: 30, ISSN: 1070-664X
  • Journal article
    Fargette N, Lavraud B, Rouillard AP, Houdayer PS, Phan TD, Øieroset M, Eastwood JP, Nicolaou G, Fedorov A, Louarn P, Owen CJ, Horbury TSet al., 2023,

    Clustering of magnetic reconnection exhausts in the solar wind: An automated detection study

    , Astronomy and Astrophysics: a European journal, Vol: 674, Pages: 1-15, ISSN: 0004-6361

    Context. Magnetic reconnection is a fundamental process in astrophysical plasmas that enables the dissipation of magnetic energy at kinetic scales. Detecting this process in situ is therefore key to furthering our understanding of energy conversion in space plasmas. However, reconnection jets typically scale from seconds to minutes in situ, and as such, finding them in the decades of data provided by solar wind missions since the beginning of the space era is an onerous task.Aims. In this work, we present a new approach for automatically identifying reconnection exhausts in situ in the solar wind. We apply the algorithm to Solar Orbiter data obtained while the spacecraft was positioned at between 0.6 and 0.8 AU and perform a statistical study on the jets we detect.Methods. The method for automatic detection is inspired by the visual identification process and strongly relies on the Walén relation. It is enhanced through the use of Bayesian inference and physical considerations to detect reconnection jets with a consistent approach.Results. Applying the detection algorithm to one month of Solar Orbiter data near 0.7 AU, we find an occurrence rate of seven jets per day, which is significantly higher than in previous studies performed at 1 AU. We show that they tend to cluster in the solar wind and are less likely to occur in the tenuous solar wind (< 10 cm−3 near 0.7 AU). We discuss why the source and the degree of Alfvénicity of the solar wind might have an impact on magnetic reconnection occurrence.Conclusions. By providing a tool to quickly identify potential magnetic reconnection exhausts in situ, we pave the way for broader statistical studies on magnetic reconnection in diverse plasma environments.

  • Journal article
    Concepcion F, Clear CP, Ding M, Pickering JCet al., 2023,

    The Laboratory Astrophysics Programme at Imperial College London

    , EUROPEAN PHYSICAL JOURNAL D, Vol: 77, ISSN: 1434-6060

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://www.imperial.ac.uk:80/respub/WEB-INF/jsp/search-t4-html.jsp Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=214&limit=30&page=4&respub-action=search.html Current Millis: 1709248535252 Current Time: Thu Feb 29 23:15:35 GMT 2024