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Journal articleBlanc M, Prieto-Ballesteros O, Andre N, et al., 2020,
Joint Europa Mission (JEM) a multi-scale study of Europa to characterize its habitability and search for extant life
, Planetary and Space Science, Vol: 193, ISSN: 0032-0633Europa is the closest and probably the most promising target to search for extant life in the Solar System, based oncomplementary evidence that it may fulfil the key criteria for habitability: the Galileo discovery of a sub-surface ocean;the many indications that the ice shell is active and may be partly permeable to transfer of chemical species,biomolecules and elementary forms of life; the identification of candidate thermal and chemical energy sourcesnecessary to drive a metabolic activity near the ocean floor. In this article we are proposing that ESA collaborates withNASA to design and fly jointly an ambitious and exciting planetary mission, which we call the Joint Europa Mission(JEM), to reach two objectives: perform a full characterization of Europa’s habitability with the capabilities of a Europaorbiter, and search for bio-signatures in the environment of Europa (surface, subsurface and exosphere) by thecombination of an orbiter and a lander. JEM can build on the advanced understanding of this system which themissions preceding JEM will provide: Juno, JUICE and Europa Clipper, and on the Europa lander concept currentlydesigned by NASA (Maize, report to OPAG, 2019). We propose the following overarching goals for our proposed JointEuropa Mission (JEM): Understand Europa as a complex system responding to Jupiter system forcing, characterisethe habitability of its potential biosphere, and search for life at its surface and in its sub-surface and exosphere. Weaddress these goals by a combination of five Priority Scientific Objectives, each with focused measurement objectivesproviding detailed constraints on the science payloads and on the platforms used by the mission. The JEM observationstrategy will combine three types of scientific measurement sequences: measurements on a high-latitude, low-altitudeEuropan orbit; in-situ measurements to be performed at the surface, using a soft lander; and measurements during thefinal descent to Europa’s surface. T
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Journal articleGraven H, Keeling RF, Rogelj J, 2020,
Changes to carbon isotopes in atmospheric CO2 over the industrial era and into the future
, Global Biogeochemical Cycles: an international journal of global change, Vol: 34, Pages: 1-21, ISSN: 0886-6236In this “Grand Challenges” paper, we review how the carbon isotopic composition of atmospheric CO2 has changed since the Industrial Revolution due to human activities and their influence on the natural carbon cycle, and we provide new estimates of possible future changes for a range of scenarios. Emissions of CO2 from fossil fuel combustion and land use change reduce the ratio of 13C/12C in atmospheric CO2 (δ13CO2). This is because 12C is preferentially assimilated during photosynthesis and δ13C in plant-derived carbon in terrestrial ecosystems and fossil fuels is lower than atmospheric δ13CO2. Emissions of CO2 from fossil fuel combustion also reduce the ratio of 14C/C in atmospheric CO2 (Δ14CO2) because 14C is absent in million-year-old fossil fuels, which have been stored for much longer than the radioactive decay time of 14C. Atmospheric Δ14CO2 rapidly increased in the 1950s to 1960s because of 14C produced during nuclear bomb testing. The resulting trends in δ13C and Δ14C in atmospheric CO2 are influenced not only by these human emissions but also by natural carbon exchanges that mix carbon between the atmosphere and ocean and terrestrial ecosystems. This mixing caused Δ14CO2 to return toward preindustrial levels in the first few decades after the spike from nuclear testing. More recently, as the bomb 14C excess is now mostly well mixed with the decadally overturning carbon reservoirs, fossil fuel emissions have become the main factor driving further decreases in atmospheric Δ14CO2. For δ13CO2, in addition to exchanges between reservoirs, the extent to which 12C is preferentially assimilated during photosynthesis appears to have increased, slowing down the recent δ13CO2 trend slightly. A new compilation of ice core and flask δ13CO2 observations indicates that the decline in δ13CO2 since the preindustrial period is less than some prior estimates, which may have incorporated
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Journal articleHeyns MJ, Gaunt CT, Lotz S, et al., 2020,
Data driven transfer functions and transmission network parameters for GIC modelling
, ELECTRIC POWER SYSTEMS RESEARCH, Vol: 188, ISSN: 0378-7796- Author Web Link
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- Citations: 6
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Journal articleChen Y, Hu Q, Zhao L, et al., 2020,
Small-scale Magnetic Flux Ropes in the First Two Parker Solar Probe Encounters
, ASTROPHYSICAL JOURNAL, Vol: 903, ISSN: 0004-637X- Author Web Link
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- Citations: 19
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Journal articleChen Y, Toth G, Hietala H, et al., 2020,
Magnetohydrodynamic with embedded particle‐in‐cell simulation of the Geospace Environment Modeling dayside kinetic processes challenge event
, Earth and Space Science, Vol: 7, Pages: 1-15, ISSN: 2333-5084We use the MHD with embedded particle‐in‐cell model (MHD‐EPIC) to study the Geospace Environment Modeling (GEM) dayside kinetic processes challenge event at 01:50‐03:00 UT on 2015‐11‐18, when the magnetosphere was driven by a steady southward IMF. In the MHD‐EPIC simulation, the dayside magnetopause is covered by a PIC code so that the dayside reconnection is properly handled. We compare the magnetic fields and the plasma profiles of the magnetopause crossing with the MMS3 spacecraft observations. Most variables match the observations well in the magnetosphere, in the magnetosheath, and also during the current sheet crossing. The MHD‐EPIC simulation produces flux ropes, and we demonstrate that some magnetic field and plasma features observed by the MMS3 spacecraft can be reproduced by a flux rope crossing event. We use an algorithm to automatically identify the reconnection sites from the simulation results. It turns out that there are usually multiple X‐lines at the magnetopause. By tracing the locations of the X‐lines, we find the typical moving speed of the X‐line endpoints is about 70~km/s, which is higher than but still comparable with the ground‐based observations.
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Journal articleBarnes D, Davies JA, Harrison RA, et al., 2020,
CMEs in the heliosphere: III. a statistical analysis of the kinematic properties derived from stereoscopic geometrical modelling techniques applied to CMEs detected in the heliosphere from 2008 to 2014 by STEREO/HI-1
, Solar Physics: a journal for solar and solar-stellar research and the study of solar terrestrial physics, Vol: 295, Pages: 1-25, ISSN: 0038-0938We present an analysis of coronal mass ejections (CMEs) observed by the Heliospheric Imagers (HIs) onboard NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft. Between August 2008 and April 2014 we identify 273 CMEs that are observed simultaneously, by the HIs on both spacecraft. For each CME, we track the observed leading edge, as a function of time, from both vantage points, and apply the Stereoscopic Self-Similar Expansion (SSSE) technique to infer their propagation throughout the inner heliosphere. The technique is unable to accurately locate CMEs when their observed leading edge passes between the spacecraft; however, we are able to successfully apply the technique to 151, most of which occur once the spacecraft-separation angle exceeds 180∘, during solar maximum. We find that using a small half-width to fit the CME can result in inferred acceleration to unphysically high velocities and that using a larger half-width can fail to accurately locate the CMEs close to the Sun because the method does not account for CME over-expansion in this region. Observed velocities from SSSE are found to agree well with single-spacecraft (SSEF) analysis techniques applied to the same events. CME propagation directions derived from SSSE and SSEF analysis agree poorly because of known limitations present in the latter.
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Journal articleMalaspina DM, Goodrich K, Livi R, et al., 2020,
Plasma Double Layers at the Boundary Between Venus and the Solar Wind
, GEOPHYSICAL RESEARCH LETTERS, Vol: 47, ISSN: 0094-8276- Author Web Link
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- Citations: 14
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Journal articleBaumjohann W, Matsuoka A, Narita Y, et al., 2020,
The BepiColombo-Mio magnetometer en route to Mercury
, Space Science Reviews, Vol: 216, Pages: 1-33, ISSN: 0038-6308The fluxgate magnetometer MGF on board the Mio spacecraft of the BepiColombo mission is introduced with its science targets, instrument design, calibration report, and scientific expectations. The MGF instrument consists of two tri-axial fluxgate magnetometers. Both sensors are mounted on a 4.8-m long mast to measure the magnetic field around Mercury at distances from near surface (initial peri-center altitude is 590 km) to 6 planetary radii (11640 km). The two sensors of MGF are operated in a fully redundant way, each with its own electronics, data processing and power supply units. The MGF instrument samples the magnetic field at a rate of up to 128 Hz to reveal rapidly-evolving magnetospheric dynamics, among them magnetic reconnection causing substorm-like disturbances, field-aligned currents, and ultra-low-frequency waves. The high time resolution of MGF is also helpful to study solar wind processes (through measurements of the interplanetary magnetic field) in the inner heliosphere. The MGF instrument firmly corroborates measurements of its companion, the MPO magnetometer, by performing multi-point observations to determine the planetary internal field at higher multi-pole orders and to separate temporal fluctuations from spatial variations.
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Journal articleQu Y, Voulgarakis A, Wang T, et al., 2020,
A study of the effect of aerosols on surface ozone through meteorologyfeedbacks over China
<jats:p>Abstract. Interactions between aerosols and gases in the atmosphere have been the focus of an increasing number of studies in recent years. Here, we focus on aerosol effects on tropospheric ozone that involve meteorological feedbacks induced by aerosol-radiation interactions. Specifically, we study the effects that involve aerosol influences on the transport of gaseous pollutants and on atmospheric moisture, both of which can impact ozone chemistry. For this purpose, we use the UK Earth System Model (UKESM1) with which we performed sensitivity simulations including and excluding the aerosol direct radiative effect (ADE) on atmospheric chemistry, and focused our analysis on an area with high aerosol presence, namely China. By comparing the simulations, we found that ADE reduced the shortwave radiation by 11 % in China, and consequently led to lower turbulent kinetic energy, weaker horizontal winds and a shallower boundary layer (with a maximum of 102.28 m reduction in north China). On the one hand, the suppressed boundary layer limited the export and diffusion of pollutants, and increased the concentration of CO, SO2, NO, NO2, PM2.5 and PM10 in the aerosol rich regions. The NO / NO2 ratio generally increased and led to more ozone depletion. On the other hand, the boundary layer top acted as a barrier that trapped moisture at lower altitudes and reduced the moisture at higher altitudes (the specific humidity was reduced by 1.69 % at 1493 m averaged in China). Due to reduced water vapor, fewer clouds were formed, and more sunlight reached the surface, so the photolytical production of ozone increased. Under the combined effect of the two meteorology feedback methods, the annual average ozone concentration in China declined by 2.01 ppb (6.2 %), which was found to bring the model in closer agreement with surface ozone measurements from different parts of China. </jats:p>
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Journal articleQu Y, Voulgarakis A, Wang T, et al., 2020,
Supplementary material to &quot;A study of the effect of aerosols on surface ozone through meteorologyfeedbacks over China&quot;
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Journal articleSparks N, Toumi R, 2020,
Pacific subsurface ocean temperature as a long-rangepredictor of South China tropical cyclone landfall
, Communications Earth & Environment, Vol: 1, ISSN: 2662-4435Seasonal forecasts of the tropical cyclones which frequently make landfall along the densely populated South China coast are highly desirable. Here, we analyse observations of landfalling tropical cyclones in South China and of subsurface ocean temperatures in the Pacific warm pool region, and identify the possibility of forecasts of South China tropical cyclone landfall a year ahead. Specifically, we define a subsurface temperature index, subNiño4, and build a predictive model based on subNiño4 anomalies with a robust double cross-validated forecast skill against climatology of 23%, similar in skill to existing forecasts issued much later in the spring. We suggest that subNiño4 ocean temperatures precede the surface El Niño/Southern Oscillation state by about 12 months, and that the zonal shifts in atmospheric heating then change mid-level winds to steer tropical cyclones towards landfall in South China. We note that regional subsurface ocean temperature anomalies may permit atmospheric predictions in other locations at a longer range than is currently thought possible.
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Journal articleFletcher, Helled, Roussos, et al., 2020,
Ice giant systems: the scientific potential of orbital missions to Uranus and Neptune
, Planetary and Space Science, Vol: 191, ISSN: 0032-0633Uranus and Neptune, and their diverse satellite and ring systems, represent the least explored environments of our Solar System, and yet may provide the archetype for the most common outcome of planetary formation throughout our galaxy. Ice Giants will be the last remaining class of Solar System planet to have a dedicated orbital explorer, and international efforts are under way to realise such an ambitious mission in the coming decades. In 2019, the European Space Agency released a call for scientific themes for its strategic science planning process for the 2030s and 2040s, known as Voyage 2050. We used this opportunity to review our present-day knowledge of the Uranus and Neptune systems, producing a revised and updated set of scientific questions and motivations for their exploration. This review article describes how such a mission could explore their origins, ice-rich interiors, dynamic atmospheres, unique magnetospheres, and myriad icy satellites, to address questions at the heart of modern planetary science. These two worlds are superb examples of how planets with shared origins can exhibit remarkably different evolutionary paths: Neptune as the archetype for Ice Giants, whereas Uranus may be atypical. Exploring Uranus' natural satellites and Neptune's captured moon Triton could reveal how Ocean Worlds form and remain active, redefining the extent of the habitable zone in our Solar System. For these reasons and more, we advocate that an Ice Giant System explorer should become a strategic cornerstone mission within ESA's Voyage 2050 programme, in partnership with international collaborators, and targeting launch opportunities in the early 2030s.
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Journal articlePickering JC, Teresa Belmonte M, Clear CP, et al., 2020,
Recent advances in experimental laboratory astrophysics for stellar astrophysics applications and future data needs
, Proceedings of the International Astronomical Union, Vol: 15, Pages: 220-228, ISSN: 1743-9213Accurate atomic data for line wavelengths, energy levels, line broadening such as hyperfine structure and isotope structure, and f-values, particularly for the line rich iron group elements, are needed for stellar astrophysics applications, and examples of recent measurements are given. These atomic data are essential for determination of elemental abundances in astronomical objects. With modern facilities, telescopes and spectrographs, access to underexplored regions (IR, UV, VUV), and improved stellar atmosphere models (3D, NLTE), and extremely large datasets, astronomers are tackling problems ranging from studying Galactic chemical evolution, to low mass stars and exoplanets. Such advances require improved accuracy and completeness of the atomic database for analyses of astrophysical spectra.
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Journal articleTeixeira JC, Folberth G, O'Connor FM, et al., 2020,
Coupling interactive fire with atmospheric composition and climatein the UK Earth System Model
<jats:p>Abstract. Fire constitutes a key process in the Earth system (ES) being driven by climate as well as affecting the climate by changing atmospheric composition and impacting the terrestrial carbon cycle. However, studies on the effects of fires on atmospheric composition, radiative forcing and climate have been limited to date, as the current generation of ES models (ESMs) do not include fully coupled fires. The aim of this work is the development and evaluation of a fully coupled fire-composition-climate ES model. For this, the INteractive Fires and Emissions algoRithm for Natural envirOnments (INFERNO) fire model is coupled to the atmosphere-only configuration of the UK’s Earth System Model (UKESM1). This fire-atmosphere interaction through atmospheric chemistry and aerosols allows for fire emissions to influence radiation, clouds, and generally weather, which can consequently influence the meteorological drivers of fire. Additionally, INFERNO is updated based on recent developments in the literature to improve the representation of human/economic factors in the anthropogenic ignition and suppression of fire. This work presents an assessment of the effects of interactive fire coupling on atmospheric composition and climate compared to the standard UKESM1 configuration that uses prescribed fire emissions. Results show a similar performance when using the fire-atmosphere coupling (the online version of the model) when compared to the offline UKESM1 that uses prescribed fire. The model can reproduce observed present day global fire emissions of carbon monoxide (CO) and aerosols, despite underestimating the global average burnt area. However, at a regional scale there is an overestimation of fire emissions over Africa due to the misrepresentation of the underlying vegetation types and an underestimation over Equatorial Asia due to a lack of representation of peat fires. Despite this, comparing model results with observations of CO column mixing rati
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Journal articleManners HA, Masters A, 2020,
The global distribution of ultra-low-frequency waves in Jupiter's magnetosphere
, Journal of Geophysical Research, Vol: 125, ISSN: 0148-0227Jupiter's giant magnetosphere is a complex system seldom in a configuration approximating steady state, and a clear picture of its governing dynamics remains elusive. Crucial to understanding how the magnetosphere behaves on a large scale are disturbances to the system on length‐scales comparable to the cavity, which are communicated by magnetohydrodynamic waves in the ultra‐low‐frequency band (<1 mHz). In this study we used magnetometer data from multiple spacecraft to perform the first global heritage survey of these waves in the magnetosphere. To map the equatorial region, we relied on the large local‐time coverage provided by the Galileo spacecraft. Flyby encounters performed by Voyager 1 & 2, Pioneer 10 & 11 and Ulysses provided local‐time coverage of the dawn sector. We found several hundred events where significant wave power was present, with periods spanning ~5‐60 min. The majority of events consisted of multiple superposed discrete periods. Periods at ~15, ~30 and ~40 min dominated the event‐averaged spectrum, consistent with the spectra of quasi‐periodic pulsations often reported in the literature. Most events were clustered in the outer magnetosphere close to the magnetopause at noon and dusk, suggesting that an external driving mechanism may dominate. The most energetic events occurred close to the planet, though more sporadically, indicating an accumulation of wave energy in the inner magnetosphere or infrequent impulsive drivers in the region. Our findings suggest that dynamics of the system at large scales is modulated by this diverse population of waves, which permeate the magnetosphere through several cavities and waveguides.
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Journal articleMüller D, Cyr OCS, Zouganelis I, et al., 2020,
The solar orbiter mission. science overview
, Astronomy & Astrophysics, Vol: 642, Pages: 1-31, ISSN: 0004-6361Aims. Solar Orbiter, the first mission of ESA’s Cosmic Vision 2015–2025 programme and a mission of international collaboration between ESA and NASA, will explore the Sun and heliosphere from close up and out of the ecliptic plane. It was launched on 10 February 2020 04:03 UTC from Cape Canaveral and aims to address key questions of solar and heliospheric physics pertaining to how the Sun creates and controls the Heliosphere, and why solar activity changes with time. To answer these, the mission carries six remote-sensing instruments to observe the Sun and the solar corona, and four in-situ instruments to measure the solar wind, energetic particles, and electromagnetic fields. In this paper, we describe the science objectives of the mission, and how these will be addressed by the joint observations of the instruments onboard.Methods. The paper first summarises the mission-level science objectives, followed by an overview of the spacecraft and payload. We report the observables and performance figures of each instrument, as well as the trajectory design. This is followed by a summary of the science operations concept. The paper concludes with a more detailed description of the science objectives.Results. Solar Orbiter will combine in-situ measurements in the heliosphere with high-resolution remote-sensing observations of the Sun to address fundamental questions of solar and heliospheric physics. The performance of the Solar Orbiter payload meets the requirements derived from the mission’s science objectives. Its science return will be augmented further by coordinated observations with other space missions and ground-based observatories.
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Journal articlePapini E, Cicone A, Piersanti M, et al., 2020,
Multidimensional Iterative Filtering: a new approach for investigating plasma turbulence in numerical simulations
, JOURNAL OF PLASMA PHYSICS, Vol: 86, ISSN: 0022-3778 -
Journal articleAlberti T, Laurenza M, Consolini G, et al., 2020,
On the Scaling Properties of Magnetic-field Fluctuations through the Inner Heliosphere
, ASTROPHYSICAL JOURNAL, Vol: 902, ISSN: 0004-637X- Author Web Link
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- Citations: 25
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Journal articleBeth A, Altwegg K, Balsiger H, et al., 2020,
ROSINA ion zoo at Comet 67P
, Astronomy and Astrophysics: a European journal, Vol: 642, Pages: 1-23, ISSN: 0004-6361Context. The Rosetta spacecraft escorted Comet 67P/Churyumov-Gerasimenko for 2 yr along its journey through the Solar System between 3.8 and 1.24 au. Thanks to the high resolution mass spectrometer on board Rosetta, the detailed ion composition within a coma has been accurately assessed in situ for the very first time.Aims. Previous cometary missions, such as Giotto, did not have the instrumental capabilities to identify the exact nature of the plasma in a coma because the mass resolution of the spectrometers onboard was too low to separate ion species with similar masses. In contrast, the Double Focusing Mass Spectrometer (DFMS), part of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis on board Rosetta (ROSINA), with its high mass resolution mode, outperformed all of them, revealing the diversity of cometary ions.Methods. We calibrated and analysed the set of spectra acquired by DFMS in ion mode from October 2014 to April 2016. In particular, we focused on the range from 13–39 u q−1. The high mass resolution of DFMS allows for accurate identifications of ions with quasi-similar masses, separating 13C+ from CH+, for instance.Results. We confirm the presence in situ of predicted cations at comets, such as CHm+ (m = 1−4), HnO+ (n = 1−3), O+, Na+, and several ionised and protonated molecules. Prior to Rosetta, only a fraction of them had been confirmed from Earth-based observations. In addition, we report for the first time the unambiguous presence of a molecular dication in the gas envelope of a Solar System body, namely CO2++.
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Journal articleHorbury TS, OBrien H, Carrasco Blazquez I, et al., 2020,
The Solar Orbiter magnetometer
, Astronomy & Astrophysics, Vol: 642, Pages: A9-A9, ISSN: 0004-6361The magnetometer instrument on the Solar Orbiter mission is designed to measure the magnetic field local to the spacecraft continuously for the entire mission duration. The need to characterise not only the background magnetic field but also its variations on scales from far above to well below the proton gyroscale result in challenging requirements on stability, precision, and noise, as well as magnetic and operational limitations on both the spacecraft and other instruments. The challenging vibration and thermal environment has led to significant development of the mechanical sensor design. The overall instrument design, performance, data products, and operational strategy are described.
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Journal articleZouganelis I, 2020,
The Solar Orbiter Science Activity Plan: translating solar and heliospheric physics questions into action
, Astronomy & Astrophysics, Vol: 642, Pages: 1-19, ISSN: 0004-6361Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate?; (2) How do solar transients drive heliospheric variability?; (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere?; (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission’s science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit’s science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans, resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime. This allows for all four mission goals to be addressed. In this paper, w
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Journal articleMitchell JG, de Nolfo GA, Hill ME, et al., 2020,
Small Electron Events Observed by Parker Solar Probe/ISIS during Encounter 2
, ASTROPHYSICAL JOURNAL, Vol: 902, ISSN: 0004-637X- Author Web Link
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- Citations: 8
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Journal articleOwen CJ, Bruno R, Livi S, et al., 2020,
The Solar Orbiter Solar Wind Analyser (SWA) suite
, ASTRONOMY & ASTROPHYSICS, Vol: 642, ISSN: 0004-6361- Author Web Link
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- Citations: 113
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Journal articleMaksimovic M, Bale SD, Chust T, et al., 2020,
The Solar Orbiter Radio and Plasma Waves (RPW) instrument
, ASTRONOMY & ASTROPHYSICS, Vol: 642, ISSN: 0004-6361- Author Web Link
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- Citations: 64
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Journal articleRodriguez-Pacheco J, Wimmer-Schweingruber RF, Mason GM, et al., 2020,
The energetic particle detector: energetic particle instrument suite for the Solar Orbiter mission
, Astronomy and Astrophysics: a European journal, Vol: 642, Pages: 1-35, ISSN: 0004-6361After decades of observations of solar energetic particles from space-based observatories, relevant questions on particle injection, transport, and acceleration remain open. To address these scientific topics, accurate measurements of the particle properties in the inner heliosphere are needed. In this paper we describe the Energetic Particle Detector (EPD), an instrument suite that is part of the scientific payload aboard the Solar Orbiter mission. Solar Orbiter will approach the Sun as close as 0.28 au and will provide extra-ecliptic measurements beyond ∼30° heliographic latitude during the later stages of the mission. The EPD will measure electrons, protons, and heavy ions with high temporal resolution over a wide energy range, from suprathermal energies up to several hundreds of megaelectronvolts/nucleons. For this purpose, EPD is composed of four units: the SupraThermal Electrons and Protons (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), and the High-Energy Telescope (HET) plus the Instrument Control Unit that serves as power and data interface with the spacecraft. The low-energy population of electrons and ions will be covered by STEP and EPT, while the high-energy range will be measured by HET. Elemental and isotopic ion composition measurements will be performed by SIS and HET, allowing full particle identification from a few kiloelectronvolts up to several hundreds of megaelectronvolts/nucleons. Angular information will be provided by the separate look directions from different sensor heads, on the ecliptic plane along the Parker spiral magnetic field both forward and backwards, and out of the ecliptic plane observing both northern and southern hemispheres. The unparalleled observations of EPD will provide key insights into long-open and crucial questions about the processes that govern energetic particles in the inner heliosphere.
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Journal articleWalsh AP, Horbury TS, Maksimovic M, et al., 2020,
Coordination of the in situ payload of Solar Orbiter
, Astronomy and Astrophysics: a European journal, Vol: 642, Pages: 1-7, ISSN: 0004-6361Solar Orbiter’s in situ coordination working group met frequently during the development of the mission with the goal of ensuring that its in situ payload has the necessary level of coordination to maximise science return. Here we present the results of that work, namely how the design of each of the in situ instruments (EPD, MAG, RPW, SWA) was guided by the need for coordination, the importance of time synchronisation, and how science operations will be conducted in a coordinated way. We discuss the mechanisms by which instrument sampling schemes are aligned such that complementary measurements will be made simultaneously by different instruments, and how burst modes are scheduled to allow a maximum overlap of burst intervals between the four instruments (telemetry constraints mean different instruments can spend different amounts of time in burst mode). We also explain how onboard autonomy, inter-instrument communication, and selective data downlink will be used to maximise the number of transient events that will be studied using high-resolution modes of all the instruments. Finally, we briefly address coordination between Solar Orbiter’s in situ payload and other missions.
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Journal articleVelli M, Harra LK, Vourlidas A, et al., 2020,
Understanding the origins of the heliosphere: integrating observations and measurements from Parker Solar Probe, Solar Orbiter, and other space- and ground-based observatories
, Astronomy and Astrophysics: a European journal, Vol: 642, Pages: 1-13, ISSN: 0004-6361Context. The launch of Parker Solar Probe (PSP) in 2018, followed by Solar Orbiter (SO) in February 2020, has opened a new window in the exploration of solar magnetic activity and the origin of the heliosphere. These missions, together with other space observatories dedicated to solar observations, such as the Solar Dynamics Observatory, Hinode, IRIS, STEREO, and SOHO, with complementary in situ observations from WIND and ACE, and ground based multi-wavelength observations including the DKIST observatory that has just seen first light, promise to revolutionize our understanding of the solar atmosphere and of solar activity, from the generation and emergence of the Sun’s magnetic field to the creation of the solar wind and the acceleration of solar energetic particles.Aims. Here we describe the scientific objectives of the PSP and SO missions, and highlight the potential for discovery arising from synergistic observations. Here we put particular emphasis on how the combined remote sensing and in situ observations of SO, that bracket the outer coronal and inner heliospheric observations by PSP, may provide a reconstruction of the solar wind and magnetic field expansion from the Sun out to beyond the orbit of Mercury in the first phases of the mission. In the later, out-of-ecliptic portions of the SO mission, the solar surface magnetic field measurements from SO and the multi-point white-light observations from both PSP and SO will shed light on the dynamic, intermittent solar wind escaping from helmet streamers, pseudo-streamers, and the confined coronal plasma, and on solar energetic particle transport.Methods. Joint measurements during PSP–SO alignments, and magnetic connections along the same flux tube complemented by alignments with Earth, dual PSP–Earth, and SO-Earth, as well as with STEREO-A, SOHO, and BepiColumbo will allow a better understanding of the in situ evolution of solar-wind plasma flows and the full three-dimensional distribution of
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Journal articleRouillard AP, Pinto RF, Vourlidas A, et al., 2020,
Models and data analysis tools for the Solar Orbiter mission
, ASTRONOMY & ASTROPHYSICS, Vol: 642, ISSN: 0004-6361- Author Web Link
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- Citations: 42
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Journal articleDesai R, Zhang H, Davies E, et al., 2020,
Three dimensional simulations of solar wind preconditioning and the 23 July 2012 Interplanetary Coronal Mass Ejection
, Solar Physics: a journal for solar and solar-stellar research and the study of solar terrestrial physics, Vol: 295, Pages: 1-14, ISSN: 0038-0938Predicting the large-scale eruptions from the solar corona and theirpropagation through interplanetary space remains an outstanding challenge in solar- and helio-physics research. In this article, we describe three dimensional magnetohydrodynamic simulations of the inner heliosphere leading up to and including the extreme interplanetary coronal mass ejection (ICME) of 23 July 2012, developed using the code PLUTO. The simulations are driven using the output of coronal models for Carrington rotations 2125 and 2126 and, given the uncertainties in the initial conditions, are able to reproduce an event of comparable magnitude to the 23 July ICME, with similar velocity and densityprofi les at 1 au. The launch-time of this event is then varied with regards to an initial 19 July ICME and the effects of solar wind preconditioning are found to be signi ficant for an event of this magnitude and to decrease over a time-window consistent with the ballistic re filling of the depleted heliospheric sector. These results indicate that the 23 July ICME was mostly unaffected by events prior, but would have travelled even faster had it erupted closer in time to the 19 July event where it would have experienced even lower drag forces. We discuss this systematic study of solar wind preconditioning in the context of space weatherforecasting.
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Journal articleSaito M, Yang P, Huang X, et al., 2020,
Spaceborne mid‐ and far‐infrared observations improving nighttime ice cloud property retrievals
, Geophysical Research Letters, Vol: 47, Pages: 1-10, ISSN: 0094-8276Two upcoming missions are scheduled to provide novel spaceborne observations of upwelling far‐infrared spectra. In this study, the accuracy of ice cloud property retrievals using spaceborne middle‐to‐far‐infrared (MIR‐FIR) measurements is examined toward a better understanding of retrieval biases and uncertainties. Theoretical sensitivity studies demonstrate that the MIR‐FIR spectra are sensitive to ice cloud properties, thereby providing a robust means for retrieving cloud properties under nighttime conditions. However, the temperature dependence of the ice refractive index and relevant ice particle shape models need to be incorporated into the retrieval procedure to avoid systematic biases in inferring cloud optical thickness and effective particle radius. Furthermore, prior information of subpixel cloud fractions is essential to mitigation of substantial systematic retrieval biases due to inconsistent subpixel cloud fractions.
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