Found 12 entries in the Bibliography.
Showing entries from 1 through 12
| 2020 |
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Context. 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-w ... Velli, M.; Harra, L.; Vourlidas, A.; Schwadron, N.; Panasenco, O.; Liewer, P.; Müller, D.; Zouganelis, I.; St Cyr, O.; Gilbert, H.; Nieves-Chinchilla, T.; Auchère, F.; Berghmans, D.; Fludra, A.; Horbury, T.; Howard, R.; Krucker, S.; Maksimovic, M.; Owen, C.; iguez-Pacheco, Rodr\; Romoli, M.; Solanki, S.; Wimmer-Schweingruber, R.; Bale, S.; Kasper, J.; McComas, D.; Raouafi, N.; Martinez-Pillet, V.; Walsh, A.; De Groof, A.; Williams, D.; YEAR: 2020 DOI: 10.1051/0004-6361/202038245 Parker Data Used; parker solar probe; Solar Probe Plus; Solar wind; solar-terrestrial relations; Sun: atmosphere; Sun: corona; Sun: heliosphere; Sun: magnetic fields |
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Sharp Alfv\ enic Impulses in the Near-Sun Solar Wind Measurements of the near-Sun solar wind by the Parker Solar Probe have revealed the presence of large numbers of discrete Alfv\ enic impulses with an anti-sunward sense of propagation. These are similar to those previously observed near 1 au, in high speed streams over the Sun\textquoterights poles and at 60 solar radii. At 35 solar radii, however, they are typically shorter and sharper than seen elsewhere. In addition, these spikes occur in "patches" and there are also clear periods within the same stream when they do no ... Horbury, Timothy; Woolley, Thomas; Laker, Ronan; Matteini, Lorenzo; Eastwood, Jonathan; Bale, Stuart; Velli, Marco; Chandran, Benjamin; Phan, Tai; Raouafi, Nour; Goetz, Keith; Harvey, Peter; Pulupa, Marc; Klein, K.; de Wit, Thierry; Kasper, Justin; Korreck, Kelly; Case, A.; Stevens, Michael; Whittlesey, Phyllis; Larson, Davin; MacDowall, Robert; Malaspina, David; Livi, Roberto; YEAR: 2020 DOI: 10.3847/1538-4365/ab5b15 |
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Parker Solar Probe In Situ Observations of Magnetic Reconnection Exhausts during Encounter 1 Magnetic reconnection in current sheets converts magnetic energy into particle energy. The process may play an important role in the acceleration and heating of the solar wind close to the Sun. Observations from Parker Solar Probe (PSP) provide a new opportunity to study this problem, as it measures the solar wind at unprecedented close distances to the Sun. During the first orbit, PSP encountered a large number of current sheets in the solar wind through perihelion at 35.7 solar radii. We performed a comprehensive survey ... Phan, T.; Bale, S.; Eastwood, J.; Lavraud, B.; Drake, J.; Oieroset, M.; Shay, M.; Pulupa, M.; Stevens, M.; MacDowall, R.; Case, A.; Larson, D.; Kasper, J.; Whittlesey, P.; Szabo, A.; Korreck, K.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; Horbury, T.; Livi, R.; Malaspina, D.; Paulson, K.; Raouafi, N.; Velli, M.; YEAR: 2020 DOI: 10.3847/1538-4365/ab55ee Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
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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.; YEAR: 2020 DOI: 10.1051/0004-6361/201937064 parker solar probe; plasmas; Solar Probe Plus; Solar wind; Sun: corona; Sun: heliosphere; turbulence |
| 2019 |
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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.; 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; 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; 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; 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; 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; 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 |
| 2016 |
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The FIELDS Instrument Suite for Solar Probe Plus NASA\textquoterights Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument conce ... Bale, S.; Goetz, K.; Harvey, P.; Turin, P.; Bonnell, J.; de Wit, T.; Ergun, R.; MacDowall, R.; Pulupa, M.; Andre, M.; Bolton, M.; Bougeret, J.-L.; Bowen, T.; Burgess, D.; Cattell, C.; Chandran, B.; Chaston, C.; Chen, C.; Choi, M.; Connerney, J.; Cranmer, S.; Diaz-Aguado, M.; Donakowski, W.; Drake, J.; Farrell, W.; Fergeau, P.; Fermin, J.; Fischer, J.; Fox, N.; Glaser, D.; Goldstein, M.; Gordon, D.; Hanson, E.; Harris, S.; Hayes, L.; Hinze, J.; Hollweg, J.; Horbury, T.; Howard, R.; Hoxie, V.; Jannet, G.; Karlsson, M.; Kasper, J.; Kellogg, P.; Kien, M.; Klimchuk, J.; Krasnoselskikh, V.; Krucker, S.; Lynch, J.; Maksimovic, M.; Malaspina, D.; Marker, S.; Martin, P.; Martinez-Oliveros, J.; McCauley, J.; McComas, D.; McDonald, T.; Meyer-Vernet, N.; Moncuquet, M.; Monson, S.; Mozer, F.; Murphy, S.; Odom, J.; Oliverson, R.; Olson, J.; Parker, E.; Pankow, D.; Phan, T.; Quataert, E.; Quinn, T.; Ruplin, S.; Salem, C.; Seitz, D.; Sheppard, D.; Siy, A.; Stevens, K.; Summers, D.; Szabo, A.; Timofeeva, M.; Vaivads, A.; Velli, M.; Yehle, A.; Werthimer, D.; Wygant, J.; YEAR: 2016 DOI: 10.1007/s11214-016-0244-5 Coronal heating; Parker Data Used; parker solar probe; Solar Probe Plus |
| 2013 |
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We present a new data analysis method enabling the observation of magnetic field fluctuations associated with temperature anisotropy instabilities using the Ulysses spacecraft. The movement of the spacecraft away from the Sun causes the observed plasma conditions, turbulent fluctuation amplitude, magnetic field strength and important physical scales to change. We normalize wavelet power spectra of the magnetic field using local values for the proton gyroscale and large scale magnetic field fluctuation amplitude to remove ... Wicks, Robert; Matteini, Lorenzo; Horbury, Timothy; Hellinger, Petr; Roberts, Aaron; YEAR: 2013 DOI: 10.1063/1.4811048 96.50.Ci; 96.60.Hv; 96.60.Tf; 96.60.Vg; astrophysical plasma; data analysis; parker solar probe; plasma instability; solar magnetism; Solar Probe Plus; solar spectra; Solar wind; Solar wind plasma; sources of solar wind; wavelet transforms |
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