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Found 12 entries in the Bibliography.
Showing entries from 1 through 12
| 2020 |
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The Parker Solar Probe (PSP) and Solar Orbiter missions are designed to make groundbreaking observations of the Sun and interplanetary space within this decade. We show that a particularly interesting in situ observation of an interplanetary coronal mass ejection (ICME) by PSP may arise during close solar flybys (<0.1 au). During these times, the same magnetic flux rope inside an ICME could be observed in situ by PSP twice, by impacting its frontal part as well as its leg. Investigating the odds of this situation, we forecas ... Möstl, Christian; Weiss, Andreas; Bailey, Rachel; Reiss, Martin; Amerstorfer, Tanja; Hinterreiter, Jürgen; Bauer, Maike; McIntosh, Scott; Lugaz, No\; Stansby, David; Published by: The Astrophysical Journal Published on: 11/2020 YEAR: 2020 DOI: 10.3847/1538-4357/abb9a1 |
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We compare magnetic field measurements taken by the FIELDS instrument on board Parker Solar Probe (PSP) during its first solar encounter to predictions obtained by potential field source surface (PFSS) modeling. Ballistic propagation is used to connect the spacecraft to the source surface. Despite the simplicity of the model, our results show striking agreement with PSP\textquoterights first observations of the heliospheric magnetic field from ̃0.5 au (107.5 R☉) down to 0.16 au (35.7 R☉). Furthe ... Badman, Samuel; Bale, Stuart; Oliveros, Juan; Panasenco, Olga; Velli, Marco; Stansby, David; Buitrago-Casas, Juan; eville, Victor; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Kasper, Justin; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab4da7 |
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Alfv\ enic fluctuations in solar wind are an intrinsic property of fast streams, while slow intervals typically have a very low degree of Alfv\ enicity, with much more variable parameters. However, sometimes a slow wind can be highly Alfv\ enic. Here we compare three different regimes of solar wind, in terms of Alfv\ enic content and spectral properties, during a minimum phase of the solar activity and at 0.3 au. We show that fast and Alfv\ enic slow intervals share some common characteristics. This would suggest a simila ... Perrone, D.; D\textquoterightAmicis, R.; De Marco, R.; Matteini, L.; Stansby, D.; Bruno, R.; Horbury, T.; Published by: Astronomy \& Astrophysics Published on: 01/2020 YEAR: 2020 DOI: 10.1051/0004-6361/201937064 parker solar probe; plasmas; Solar Probe Plus; Solar wind; Sun: corona; Sun: heliosphere; turbulence |
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Enhanced proton parallel temperature inside patches of switchbacks in the inner heliosphere Woodham, L.; Horbury, T.; Matteini, L.; Woolley, T.; Laker, R.; Bale, S.; Nicolaou, G.; Stawarz, J.; Stansby, D.; Hietala, H.; Larson, D.; Livi, R.; Verniero, J.; McManus, M.; Kasper, J.; Korreck, K.; Raouafi, N.; Moncuquet, M.; Pulupa, M.; Published by: Astronomy and Astrophysics Published on: YEAR: 2020 DOI: "10.1051/0004-6361/202039415" |
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Sensitivity of solar wind mass flux to coronal temperature Stansby, D.; Bercic, L.; Matteini, L.; Owen, C.; French, R.; Baker, D.; Badman, S.; Published by: Astronomy and Astrophysics Published on: YEAR: 2020 DOI: "10.1051/0004-6361/202039789" |
| 2019 |
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Accurate reconstruction of global solar-wind structure is essential for connecting remote and in situ observations of solar plasma, and hence understanding formation and release of solar wind. Information can routinely be obtained from photospheric magnetograms, via coronal and solar-wind modelling, and directly from in situ observations, typically at large heliocentric distances (most commonly near 1 AU). Magnetogram-constrained modelling has the benefit of reconstructing global solar-wind structure, but with relatively lar ... Owens, Mathew; Lang, Matthew; Riley, Pete; Stansby, David; Published by: SOLAR PHYSICS Published on: JUN YEAR: 2019 DOI: 10.1007/s11207-019-1479-6 |
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Highly structured slow solar wind emerging from an equatorial coronal hole During the solar minimum, when the Sun is at its least active, the solar wind is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfv\ enic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain; theories and observations suggest that they may originate at the tips of ... Bale, S.; Badman, S.; Bonnell, J.; Bowen, T.; Burgess, D.; Case, A.; Cattell, C.; Chandran, B.; Chaston, C.; Chen, C.; Drake, J.; de Wit, Dudok; Eastwood, J.; Ergun, R.; Farrell, W.; Fong, C.; Goetz, K.; Goldstein, M.; Goodrich, K.; Harvey, P.; Horbury, T.; Howes, G.; Kasper, J.; Kellogg, P.; Klimchuk, J.; Korreck, K.; Krasnoselskikh, V.; Krucker, S.; Laker, R.; Larson, D.; MacDowall, R.; Maksimovic, M.; Malaspina, D.; Martinez-Oliveros, J.; McComas, D.; Meyer-Vernet, N.; Moncuquet, M.; Mozer, F.; Phan, T.; Pulupa, M.; Raouafi, N.; Salem, C.; Stansby, D.; Stevens, M.; Szabo, A.; Velli, M.; Woolley, T.; Wygant, J.; Published by: Nature Published on: 12/2019 YEAR: 2019 DOI: 10.1038/s41586-019-1818-7 |
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A strong correlation between speed and proton temperature has been observed, across many years, on hourly averaged measurements in the solar wind. Here, we show that this relationship is also observed at a smaller scale on intervals of a few days, within a single stream. Following the radial evolution of a well-defined stream of coronal-hole plasma, we show that the temperature-speed (T-V) relationship evolves with distance, implying that the T-V relationship at 1 au cannot be used as a proxy for that near the Sun. We sug ... Perrone, Denise; Stansby, D; Horbury, T; Matteini, L; Published by: Monthly Notices of the Royal Astronomical Society Published on: 09/2019 YEAR: 2019 DOI: 10.1093/mnras/stz1877 parker solar probe; Solar Probe Plus; Solar wind; Sun: corona; Sun: heliosphere |
| 2018 |
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A New Inner Heliosphere Proton Parameter Dataset from the Helios Mission In the near future, Parker Solar Probe and Solar Orbiter will provide the first comprehensive in-situ measurements of the solar wind in the inner heliosphere since the Helios mission in the 1970s. We describe a reprocessing of the original Helios ion distribution functions to provide reliable and reproducible data to characterise the proton core population of the solar wind in the inner heliosphere. A systematic fitting of bi-Maxwellian distribution functions was performed to the raw Helios ion distribution function data ... Stansby, David; Salem, Chadi; Matteini, Lorenzo; Horbury, Timothy; Published by: Solar Physics Published on: 11/2018 YEAR: 2018 DOI: 10.1007/s11207-018-1377-3 Astrophysics - Solar and Stellar Astrophysics; Heliosphere; Inner heliosphere; parker solar probe; Physics - Space Physics; Solar Probe Plus; Solar wind; Solar wind protons |
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Short, large-amplitude speed enhancements in the near-Sunfast solar wind We report the presence of intermittent, short discrete enhancements in plasma speed in the near-Sun high-speed solar wind. Lasting tens of seconds to minutes in spacecraft measurements at 0.3 au, speeds inside these enhancements can reach 1000 km s-1, corresponding to a kinetic energy up to twice that of the bulk high-speed solar wind. These events, which occur around 5 per cent of the time, are Alfv\ enic in nature with large magnetic field deflections and are the same temperature as the surrounding plasma, in ... Horbury, T; Matteini, L; Stansby, D; Published by: Monthly Notices of the Royal Astronomical Society Published on: 08/2018 YEAR: 2018 DOI: 10.1093/mnras/sty953 parker solar probe; Solar Probe Plus; Solar wind; Sun: corona |
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Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations Spacecraft observations have shown that the proton temperature in the solar wind falls off with radial distance more slowly than expected for an adiabatic prediction. Usually, previous studies have been focused on the evolution of the solar-wind plasma by using the bulk speed as an order parameter to discriminate different regimes. In contrast, here, we study the radial evolution of pure and homogeneous fast streams (i.e. well-defined streams of coronal-hole plasma that maintain their identity during several solar rotatio ... Perrone, Denise; Stansby, D; Horbury, T; Matteini, L; Published by: Monthly Notices of the Royal Astronomical Society Published on: 03/2019 YEAR: 2018 DOI: 10.1093/mnras/sty3348 parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus; Solar wind; Sun: corona; Sun: heliosphere |
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Diagnosing solar wind origins using in situ measurements in the inner heliosphere Robustly identifying the solar sources of individual packets of solar wind measured in interplanetary space remains an open problem. We set out to see if this problem is easier to tackle using solar wind measurements closer to the Sun than 1 au, where the mixing and dynamical interaction of different solar wind streams is reduced. Using measurements from the Helios mission, we examined how the proton core temperature anisotropy and cross-helicity varied with distance. At 0.3 au there are two clearly separated anisotropic ... Stansby, D; Horbury, T; Matteini, L; Published by: Monthly Notices of the Royal Astronomical Society Published on: 01/2019 YEAR: 2018 DOI: 10.1093/mnras/sty2814 Astrophysics - Solar and Stellar Astrophysics; parker solar probe; Physics - Space Physics; Solar Probe Plus; Solar wind; Sun:; Sun: heliosphere |
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