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Journal articleHassig M, Altwegg K, Balsiger H, et al., 2015,
Time variability and heterogeneity in the coma of 67P/Churyumov-Gerasimenko
, Science, Vol: 347, ISSN: 0036-8075Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.
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Journal articleVigren E, Galand M, Lavvas P, et al., 2015,
On the possibility of significant electron depletion due to nanograin charging in the coma of comet 67p/churyumov-gerasimenko near perihelion
, Astrophysical Journal, Vol: 798, ISSN: 1538-4357 -
Book chapterEastwood JP, Kiehas SA, 2015,
Origin and Evolution of Plasmoids and Flux Ropes in the Magnetotails of Earth and Mars
, Magnetotails in the Solar System, Pages: 269-287This chapter discusses the origin and evolution of plasmoids and flux ropes in Earth's magnetotail, providing an overview of author's current understanding based on recent multipoint and multimission data analysis. It also presents recent results concerning observations of flux ropes in the vicinity of Mars. Understanding the Mars solar wind interaction is very important for determining its atmospheric history, and recent discoveries show that magnetic reconnection-generated structures may play a significant role, particularly in the vicinity of the crustal field regions. The chapter briefly discusses some of the different terms used to describe reconnection-generated structures. It describes the production of islands, plasmoids, and secondary islands by antiparallel reconnection.
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Journal articleO'Reilly CH, Czaja A, 2015,
The response of the Pacific storm track and atmospheric circulation to Kuroshio Extension variability
, Quarterly Journal of the Royal Meteorological Society, Vol: 141, Pages: 52-66, ISSN: 0035-9009An index of the Kuroshio Extension front strength is produced using a maximum covariance analysis between sea‐surface temperature (SST) and sea‐surface height (SSH) gradient observations, and composites of the atmospheric state are presented during its positive and negative phases using reanalysis data (1992–2011).It is found that when the Kuroshio Extension is less (more) meandering, with a stronger (weaker) SST front, the atmospheric heat transport by transient eddies is increased in the western (eastern) Pacific region, consistent with an increase (decrease) in low‐level baroclinicity. Analysis of the eddy–mean flow interaction shows that this zonal shift in heat transport forces anomalous barotropic flow in the Eastern Pacific, where blocking frequency is strongly influenced.The above relationships cannot be reconciled with the known response of the North Pacific storm track to remote forcing from the Tropical Pacific, nor can they be explained by the response of the ocean to atmospheric forcing via surface heat fluxes or winds. Rather, the zonal shift in the storm track highlighted here, and the associated changes in the large‐scale circulation, are interpreted as a response to the interannual variability of the Kuroshio Extension front.
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Journal articleKlueser L, Banks JR, Martynenko D, et al., 2015,
Information content of space-borne hyperspectral infrared observations with respect to mineral dust properties
, REMOTE SENSING OF ENVIRONMENT, Vol: 156, Pages: 294-309, ISSN: 0034-4257- Author Web Link
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- Citations: 20
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Journal articleEastwood JP, Kataria DO, McInnes CR, et al., 2015,
Sunjammer
, WEATHER, Vol: 70, Pages: 27-30, ISSN: 0043-1656- Author Web Link
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- Citations: 13
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Journal articleDel Zanna L, Matteini L, Landi S, et al., 2015,
Parametric decay of parallel and oblique Alfvén waves in the expanding solar wind
, Journal of Plasma Physics, Vol: 81, ISSN: 0022-3778<jats:p>The long-term evolution of large-amplitude Alfvén waves propagating in the solar wind is investigated by performing two-dimensional MHD simulations within the expanding box model. The linear and nonlinear phases of the parametric decay instability are studied for both circularly polarized waves in parallel propagation and for arc-polarized waves in oblique propagation. The non-monochromatic case is also considered. In the oblique case, the direct excitation of daughter modes transverse to the local background field is found for the first time in an expanding environment, and this transverse cascade seems to be favored for monochromatic mother waves. The expansion effect reduces the instability growth rate, and it can even suppress its onset for the lowest frequency modes considered here, possibly explaining the persistence of these outgoing waves in the solar wind.</jats:p>
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Journal articleSparks N, Toumi R, 2015,
Numerical Simulations of Daytime Temperature and Humidity Crossover Effects in London
, BOUNDARY-LAYER METEOROLOGY, Vol: 154, Pages: 101-117, ISSN: 0006-8314- Author Web Link
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- Citations: 6
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Journal articleMasters A, 2015,
Magnetic reconnection at Neptune's magnetopause
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 479-493, ISSN: 2169-9380- Author Web Link
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- Citations: 26
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Journal articleLeitner S, Valavanoglou A, Brown P, et al., 2015,
Design of the Magnetoresistive Magnetometer for ESA's SOSMAG Project
, IEEE TRANSACTIONS ON MAGNETICS, Vol: 51, ISSN: 0018-9464- Author Web Link
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- Citations: 14
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Book chapterMitchell DG, Brandt PC, Carbary JF, et al., 2015,
Injection, Interchange, and Reconnection: Energetic Particle Observations in Saturn's Magnetosphere
, MAGNETOTAILS IN THE SOLAR SYSTEM, Editors: Keiling, Jackman, Delamere, Publisher: BLACKWELL SCIENCE PUBL, Pages: 327-343, ISBN: 978-1-118-84234-8- Author Web Link
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- Citations: 35
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Journal articleSitch S, Friedlingstein P, Gruber N, et al., 2015,
Recent trends and drivers of regional sources and sinks of carbon dioxide
, BIOGEOSCIENCES, Vol: 12, Pages: 653-679, ISSN: 1726-4170- Cite
- Citations: 701
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Journal articleMushtaq S, Steers EBM, Whitby JA, et al., 2015,
A glow discharge time-of-flight mass spectrometry (GD-TOFMS) study of the 'hydrogen effect' using copper, iron and titanium cathodes
, JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY, Vol: 30, Pages: 1774-1781, ISSN: 0267-9477- Author Web Link
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- Citations: 6
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Book chapterCargill P, 2015,
Magnetic Reconnection in the Solar Corona: Historical Perspective and Modern Thinking
, MAGNETOSPHERIC PLASMA PHYSICS: THE IMPACT OF JIM DUNGEY'S RESEARCH, Editors: Southwood, Cowley, Mitton, Publisher: SPRINGER, Pages: 221-251, ISBN: 978-3-319-18358-9 -
Journal articleForsyth C, Watt CEJ, Rae IJ, et al., 2014,
Increases in plasma sheet temperature with solar wind driving during substorm growth phases
, GEOPHYSICAL RESEARCH LETTERS, Vol: 41, Pages: 8713-8721, ISSN: 0094-8276- Cite
- Citations: 24
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Journal articleBanks JR, Brindley HE, Hobby M, et al., 2014,
The daytime cycle in dust aerosol direct radiative effects observed in the central Sahara during the Fennec campaign in June 2011
, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, Vol: 119, Pages: 13861-13876, ISSN: 2169-897X- Author Web Link
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- Citations: 17
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Journal articleBrown P, Whiteside BJ, Beek TJ, et al., 2014,
Space magnetometer based on an anisotropic magnetoresistive hybrid sensor
, Review of Scientific Instruments, Vol: 85, ISSN: 1089-7623 -
Journal articleMistry R, Eastwood JP, Hietala H, 2014,
Detection of small-scale folds at a solar wind reconnection exhaust
, Journal of Geophysical Research: Space Physics, Vol: 120, Pages: 30-42, ISSN: 2169-9402Observations of reconnection in the solar wind over the last few years appear to indicate that the majority of large-scale reconnecting current sheets are roughly planar, and that reconnection itself is quasi-steady. Most studies of solar wind exhausts have used spacecraft with large separations and relatively low time cadence ion measurements. Here we present multipoint Cluster observations of a reconnection exhaust and the associated current sheet at ACE and Wind, enabling it to be studied on multiple length scales and at high time resolution. While analysis shows that on large scales the current sheet is planar, detailed measurements using the four closely spaced Cluster spacecraft show that the trailing edge of the reconnection jet is nonplanar with folds orthogonal to the reconnection plane, with length scales of approximately 230 ion inertial lengths. Our findings thus suggest that while solar wind current sheets undergoing reconnection may be planar on large scales, they may also exhibit complex smaller-scale structure. Such structure is difficult to observe and has rarely been detected because exhausts are rapidly convected past the spacecraft in a single cut; there is therefore a limited set of spacecraft trajectories through the exhaust which would allow the nonplanar features to be intercepted. We consider how such nonplanar reconnection current sheets can form and the processes which may have generated the 3-D structure that was observed.
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Journal articleArcher MO, Turner DL, Eastwood JP, et al., 2014,
Global impacts of a Foreshock Bubble: Magnetosheath, magnetopause and ground-based observations
, Planetary and Space Science, Vol: 106, Pages: 56-66, ISSN: 1873-5088Using multipoint observations we show, for the first time, that Foreshock Bubbles (FBs) have a global impact on Earth׳s magnetosphere. We show that an FB, a transient kinetic phenomenon due to the interaction of backstreaming suprathermal ions with a discontinuity, modifies the total pressure upstream of the bow shock showing a decrease within the FB׳s core and sheath regions. Magnetosheath plasma is accelerated towards the intersection of the FB׳s current sheet with the bow shock resulting in fast, sunward, flows as well as outward motion of the magnetopause. Ground-based magnetometers also show signatures of this magnetopause motion simultaneously across at least 7 h of magnetic local time, corresponding to a distance of 21.5RE transverse to the Sun–Earth line along the magnetopause. These observed global impacts of the FB are in agreement with previous simulations and in stark contrast to the known localised, smaller scale effects of Hot Flow Anomalies (HFAs).
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Journal articleDen Hartog EA, Ruffoni MP, Lawler JE, et al., 2014,
Fe I oscillator strengths for transitions from high-lying even-parity levels
, Astrophysical Journal Supplement Series, Vol: 215, Pages: 1-13, ISSN: 0067-0049New radiative lifetimes, measured to ±5% accuracy, are reported for 31 even-parity levels of Fe I ranging from 45061 cm–1 to 56842 cm–1. These lifetimes have been measured using single-step and two-step time-resolved laser-induced fluorescence on a slow atomic beam of iron atoms. Branching fractions have been attempted for all of these levels, and completed for 20 levels. This set of levels represents an extension of the collaborative work reported in Ruffoni et al. The radiative lifetimes combined with the branching fractions yields new oscillator strengths for 203 lines of Fe I. Utilizing a 1D-LTE model of the solar photosphere, spectral syntheses for a subset of these lines which are unblended in the solar spectrum yields a mean iron abundance of langlog[ε(Fe)]rang = 7.45 ± 0.06.
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Journal articleSouthwood D, 2014,
Space science and policy
, ASTRONOMY & GEOPHYSICS, Vol: 55, Pages: 26-32, ISSN: 1366-8781 -
Journal articleGenestreti KJ, Fuselier SA, Goldstein J, et al., 2014,
The location and rate of occurrence of near-Earth magnetotail reconnection as observed by Cluster and Geotail
, JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, Vol: 121, Pages: 98-109, ISSN: 1364-6826- Author Web Link
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- Citations: 33
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Journal articleQureshi MNS, Nasir W, Masood W, et al., 2014,
Terrestrial lion roars and non-Maxwellian distribution
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 119, ISSN: 2169-9380- Author Web Link
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- Citations: 81
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Journal articleHunt GJ, Cowley SWH, Provan G, et al., 2014,
Field-aligned currents in Saturn's southern nightside magnetosphere: Subcorotation and planetary period oscillation components
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 119, ISSN: 2169-9380- Author Web Link
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- Citations: 91
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Journal articleMasters A, Achilleos N, Agnor CB, et al., 2014,
Neptune and Triton: Essential pieces of the Solar System puzzle
, PLANETARY AND SPACE SCIENCE, Vol: 104, Pages: 108-121, ISSN: 0032-0633- Cite
- Citations: 32
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Journal articleCoustenis A, Atreya S, Castillo J, et al., 2014,
Surfaces, atmospheres and magnetospheres of the outer planets and their satellites and ring systems: Part X Preface
, PLANETARY AND SPACE SCIENCE, Vol: 104, Pages: 1-2, ISSN: 0032-0633 -
Journal articleBalogh A, Hudson HS, Petrovay K, et al., 2014,
Introduction to the Solar Activity Cycle: Overview of Causes and Consequences
, SPACE SCIENCE REVIEWS, Vol: 186, Pages: 1-15, ISSN: 0038-6308- Author Web Link
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- Citations: 47
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Journal articleArridge CS, Achilleos N, Agarwal J, et al., 2014,
The science case for an orbital mission to Uranus: Exploring the origins and evolution of ice giant planets
, PLANETARY AND SPACE SCIENCE, Vol: 104, Pages: 122-140, ISSN: 0032-0633- Cite
- Citations: 59
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Journal articleChen CHK, Leung L, Boldyrev S, et al., 2014,
Ion-scale spectral break of solar wind turbulence at high and low beta
, GEOPHYSICAL RESEARCH LETTERS, Vol: 41, Pages: 8081-8088, ISSN: 0094-8276- Author Web Link
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- Citations: 156
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Journal articleVigren E, Galand M, Yelle RV, et al., 2014,
Ionization balance in Titan's nightside ionosphere
, Icarus, Vol: 248, Pages: 539-546, ISSN: 0019-1035
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