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Found 26 entries in the Bibliography.
Showing entries from 1 through 26
| 2023 |
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New Observations of Solar Wind 1/f Turbulence Spectrum from Parker Solar Probe The trace magnetic power spectrum in the solar wind is known to be characterized by a double power law at scales much larger than the proton gyro-radius, with flatter spectral exponents close to -1 found at the lower frequencies below an inertial range with indices closer to [-1.5, -1.67]. The origin of the 1/f range is still under debate. In this study, we selected 109 magnetically incompressible solar wind intervals (\ensuremath\delta\ensuremath\mid B \ensuremath\mid/\ensuremath\mid B \ensuremath\mid \ensuremath\ll 1) from ... Huang, Zesen; Sioulas, Nikos; Shi, Chen; Velli, Marco; Bowen, Trevor; Davis, Nooshin; Chandran, B.~D.~G.; Matteini, Lorenzo; Kang, Ning; Shi, Xiaofei; Huang, Jia; Bale, Stuart; Kasper, J.~C.; Larson, Davin; Livi, Roberto; Whittlesey, P.~L.; Rahmati, Ali; Paulson, Kristoff; Stevens, M.; Case, A.~W.; de Wit, Thierry; Malaspina, David; Bonnell, J.~W.; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Published by: \apjl Published on: jun YEAR: 2023 DOI: 10.3847/2041-8213/acd7f2 Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; Space plasmas; Heliosphere; Alfven waves; 1534; 830; 1964; 1544; 711; 23; Astrophysics - Solar and Stellar Astrophysics; Physics - Fluid Dynamics; Physics - Geophysics; Physics - Plasma Physics; Physics - Space Physics |
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Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum Launched on 12 Aug. 2018, NASA s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission s primary science goal is to determine the structure and dynamics of the Sun s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number ... Raouafi, N.~E.; Matteini, L.; Squire, J.; Badman, S.~T.; Velli, M.; Klein, K.~G.; Chen, C.~H.~K.; Matthaeus, W.~H.; Szabo, A.; Linton, M.; Allen, R.~C.; Szalay, J.~R.; Bruno, R.; Decker, R.~B.; Akhavan-Tafti, M.; Agapitov, O.~V.; Bale, S.~D.; Bandyopadhyay, R.; Battams, K.; Ber\vci\vc, L.; Bourouaine, S.; Bowen, T.~A.; Cattell, C.; Chandran, B.~D.~G.; Chhiber, R.; Cohen, C.~M.~S.; Amicis, R.; Giacalone, J.; Hess, P.; Howard, R.~A.; Horbury, T.~S.; Jagarlamudi, V.~K.; Joyce, C.~J.; Kasper, J.~C.; Kinnison, J.; Laker, R.; Liewer, P.; Malaspina, D.~M.; Mann, I.; McComas, D.~J.; Niembro-Hernandez, T.; Nieves-Chinchilla, T.; Panasenco, O.; y, Pokorn\; Pusack, A.; Pulupa, M.; Perez, J.~C.; Riley, P.; Rouillard, A.~P.; Shi, C.; Stenborg, G.; Tenerani, A.; Verniero, J.~L.; Viall, N.; Vourlidas, A.; Wood, B.~E.; Woodham, L.~D.; Woolley, T.; Published by: ßr Published on: feb YEAR: 2023 DOI: 10.1007/s11214-023-00952-4 Parker Data Used; Sun; Corona; Solar wind; plasma; magnetic fields; coronal mass ejections; parker solar probe; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
| 2022 |
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Switchback deflections beyond the early parker solar probe encounters Switchbacks are Aflv\ enic fluctuations in the solar wind, which exhibit large rotations in the magnetic field direction. Observations from Parker Solar Probe s (PSP s) first two solar encounters have formed the basis for many of the described switchback properties and generation mechanisms. However, this early data may not be representative of the typical near-Sun solar wind, biasing our current understanding of these phenomena. One defining switchback property is the magnetic deflection direction. During the first solar en ... Laker, R.; Horbury, T.~S.; Matteini, L.; Bale, S.~D.; Stawarz, J.~E.; Woodham, L.~D.; Woolley, T.; Published by: \mnras Published on: nov YEAR: 2022 DOI: 10.1093/mnras/stac2477 Parker Data Used; Sun: magnetic fields; Sun: heliosphere; Solar wind; Physics - Space Physics |
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Density and Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks McManus, Michael; Verniero, Jaye; Bale, Stuart; Bowen, Trevor; Larson, Davin; Kasper, Justin; Livi, Roberto; Matteini, Lorenzo; Rahmati, Ali; Romeo, Orlando; Whittlesey, Phyllis; Woolley, Thomas; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6ba3 Parker Data Used; Heliosphere; Solar wind; Space plasmas; 711; 1534; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Franci, Luca; Papini, Emanuele; Del Sarto, Daniele; Hellinger, Petr; Burgess, David; Matteini, Lorenzo; Landi, Simone; Montagud-Camps, Victor; Published by: Universe Published on: aug YEAR: 2022 DOI: 10.3390/universe8090453 |
| 2021 |
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Evolution of Switchbacks in the Inner Heliosphere We analyze magnetic field data from the first six encounters of Parker Solar Probe, three Helios fast streams and two Ulysses south polar passes covering heliocentric distances 0.1 \ensuremath\lesssim R \ensuremath\lesssim 3 au. We use this data set to statistically determine the evolution of switchbacks of different periods and amplitudes with distance from the Sun. We compare the radial evolution of magnetic field variances with that of the mean square amplitudes of switchbacks, and quantify the radial evolution of the cum ... Tenerani, Anna; Sioulas, Nikos; Matteini, Lorenzo; Panasenco, Olga; Shi, Chen; Velli, Marco; Published by: \apjl Published on: oct YEAR: 2021 DOI: 10.3847/2041-8213/ac2606 Parker Data Used; Heliosphere; Solar wind; interplanetary turbulence; Alfven waves; Space plasmas; 711; 1534; 830; 23; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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One of the striking observations from the Parker Solar Probe (PSP) spacecraft is the prevalence in the inner heliosphere of large amplitude, Alfv\ enic magnetic field reversals termed switchbacks. These $\delta B_R/B\sim \mathcal O (1$ ) fluctuations occur over a range of timescales and in patches separated by intervals of quiet, radial magnetic field. We use measurements from PSP to demonstrate that patches of switchbacks are localized within the extensions of plasma structures originating at the base of the corona. These ... Bale, S.~D.; Horbury, T.~S.; Velli, M.; Desai, M.~I.; Halekas, J.~S.; McManus, M.~D.; Panasenco, O.; Badman, S.~T.; Bowen, T.~A.; Chandran, B.~D.~G.; Drake, J.~F.; Kasper, J.~C.; Laker, R.; Mallet, A.; Matteini, L.; Phan, T.~D.; Raouafi, N.~E.; Squire, J.; Woodham, L.~D.; Woolley, T.; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2d8c Parker Data Used; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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First Solar Orbiter observation of the Alfv\ enic slow wind and identification of its solar source Context. Turbulence dominated by large-amplitude, nonlinear Alfv\ en-like fluctuations mainly propagating away from the Sun is ubiquitous in high-speed solar wind streams. Recent studies have demontrated that slow wind streams may also show strong Alfv\ enic signatures, especially in the inner heliosphere. \ Aims: The present study focuses on the characterisation of an Alfv\ enic slow solar wind interval observed by Solar Orbiter between 14 and 18 July 2020 at a heliocentric distance of 0.64 AU. \ Methods: Our analysis is ba ... Amicis, R.; Bruno, R.; Panasenco, O.; Telloni, D.; Perrone, D.; Marcucci, M.~F.; Woodham, L.; Velli, M.; De Marco, R.; Jagarlamudi, V.; Coco, I.; Owen, C.; Louarn, P.; Livi, S.; Horbury, T.; e, Andr\; Angelini, V.; Evans, V.; Fedorov, A.; Genot, V.; Lavraud, B.; Matteini, L.; Müller, D.; Brien, H.; Pezzi, O.; Rouillard, A.~P.; Sorriso-Valvo, L.; Tenerani, A.; Verscharen, D.; Zouganelis, I.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140938 Parker Data Used; Interplanetary medium; Solar wind; methods: data analysis; magnetohydrodynamics (MHD); turbulence; Sun: general |
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Context. The recent launches of Parker Solar Probe, Solar Orbiter (SO), and BepiColombo, along with several older spacecraft, have provided the opportunity to study the solar wind at multiple latitudes and distances from the Sun simultaneously. \ Aims: We take advantage of this unique spacecraft constellation, along with low solar activity across two solar rotations between May and July 2020, to investigate how the solar wind structure, including the heliospheric current sheet (HCS), varies with latitude. \ Methods: We visua ... Laker, R.; Horbury, T.~S.; Bale, S.~D.; Matteini, L.; Woolley, T.; Woodham, L.~D.; Stawarz, J.~E.; Davies, E.~E.; Eastwood, J.~P.; Owens, M.~J.; Brien, H.; Evans, V.; Angelini, V.; Richter, I.; Heyner, D.; Owen, C.~J.; Louarn, P.; Fedorov, A.; Published by: \aap Published on: aug YEAR: 2021 DOI: 10.1051/0004-6361/202140679 Sun: coronal mass ejections (CMEs); Solar wind; Sun: heliosphere; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used |
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The Parker Solar Probe (PSP) mission presents a unique opportunity to study the near-Sun solar wind closer than any previous spacecraft. During its fourth and fifth solar encounters, PSP had the same orbital trajectory, meaning that solar wind was measured at the same latitudes and radial distances. We identify two streams measured at the same heliocentric distance (\raisebox-0.5ex\textasciitilde0.13au) and latitude (\raisebox-0.5ex\textasciitilde-3.5$^○$) across these encounters to reduce spatial evolution effects. By com ... Woolley, Thomas; Matteini, Lorenzo; McManus, Michael; Ber\vci\vc, Laura; Badman, Samuel; Woodham, Lloyd; Horbury, Timothy; Bale, Stuart; Laker, Ronan; Stawarz, Julia; Larson, Davin; Published by: \mnras Published on: aug YEAR: 2021 DOI: 10.1093/mnras/stab2281 Sun: heliosphere; Solar wind; magnetic fields; Parker Data Used |
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The Parker Solar Probe (PSP) routinely observes magnetic field deflections in the solar wind at distances less than 0.3 au from the Sun. These deflections are related to structures commonly called "switchbacks" (SBs), whose origins and characteristic properties are currently debated. Here, we use a database of visually selected SB intervals—and regions of solar wind plasma measured just before and after each SB—to examine plasma parameters, turbulent spectra from inertial to dissipation scales, and intermittency ... Martinovic, Mihailo; Klein, Kristopher; Huang, Jia; Chandran, Benjamin; Kasper, Justin; Lichko, Emily; Bowen, Trevor; Chen, Christopher; Matteini, Lorenzo; Stevens, Michael; Case, Anthony; Bale, Stuart; Published by: The Astrophysical Journal Published on: 05/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abebe5 Parker Data Used; Space plasmas; interplanetary turbulence; Solar wind; 1544; 830; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
| 2020 |
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Statistical analysis of orientation, shape, and size of solar wind switchbacks Context. One of the main discoveries from the first two orbits of Parker Solar Probe (PSP) was the presence of magnetic switchbacks, whose deflections dominated the magnetic field measurements. Determining their shape and size could provide evidence of their origin, which is still unclear. Previous work with a single solar wind stream has indicated that these are long, thin structures although the direction of their major axis could not be determined. \ Aims: We investigate if this long, thin nature extends to other solar wi ... Laker, R.; Horbury, T.; Bale, S.; Matteini, L.; Woolley, T.; Woodham, L.; Badman, S.; Pulupa, M.; Kasper, J.; Stevens, M.; Case, A.; Korreck, K.; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2020 DOI: "10.1051/0004-6361/202039354" |
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Enhanced proton parallel temperature inside patches of switchbacks in the inner heliosphere Context. Switchbacks are discrete angular deflections in the solar wind magnetic field that have been observed throughout the heliosphere. Recent observations by Parker Solar Probe (PSP) have revealed the presence of patches of switchbacks on the scale of hours to days, separated by quieter radial fields. \ Aims: We aim to further diagnose the origin of these patches using measurements of proton temperature anisotropy that can illuminate possible links to formation processes in the solar corona. \ Methods: We fitted 3D bi- ... 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: jun YEAR: 2020 DOI: "10.1051/0004-6361/202039415" |
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Sensitivity of solar wind mass flux to coronal temperature Solar wind models predict that the mass flux carried away from the Sun in the solar wind should be extremely sensitive to the temperature in the corona, where the solar wind is accelerated. We perform a direct test of this prediction in coronal holes and active regions using a combination of in situ and remote sensing observations. For coronal holes, a 50\% increase in temperature from 0.8 to 1.2 MK is associated with a tripling of the coronal mass flux. This trend is maintained within active regions at temperatures over 2 M ... Stansby, D.; Bercic, L.; Matteini, L.; Owen, C.; French, R.; Baker, D.; Badman, S.; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2020 DOI: "10.1051/0004-6361/202039789" |
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Proton core behaviour inside magnetic field switchbacks During Parker Solar Probe s first two orbits, there are widespread observations of rapid magnetic field reversals known as switchbacks. These switchbacks are extensively found in the near-Sun solar wind, appear to occur in patches, and have possible links to various phenomena such as magnetic reconnection near the solar surface. As switchbacks are associated with faster plasma flows, we questioned whether they are hotter than the background plasma and whether the microphysics inside a switchback is different to its surroundi ... Woolley, Thomas; Matteini, Lorenzo; Horbury, Timothy; Bale, Stuart; Woodham, Lloyd; Laker, Ronan; Alterman, Benjamin; Bonnell, John; Case, Anthony; Kasper, Justin; Klein, Kristopher; Martinovic, Mihailo; Stevens, Michael; Published by: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Published on: 11/2020 YEAR: 2020 DOI: 10.1093/mnras/staa2770 |
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The shape of the electron velocity distribution function plays an important role in the dynamics of the solar wind acceleration. Electrons are normally modeled with three components, the core, the halo, and the strahl. We investigate how well the fast strahl electrons in the inner heliosphere preserve the information about the coronal electron temperature at their origin. We analyzed the data obtained by two missions, Helios, spanning the distances between 65 and 215 RS, and Parker Solar Probe (PSP), reaching d ... Bercic, Laura; Larson, Davin; Whittlesey, Phyllis; Maksimovic, Milan; Badman, Samuel; Landi, Simone; Matteini, Lorenzo; Bale, Stuart.; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Kasper, Justin; Korreck, Kelly; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Stevens, Michael; Published by: The Astrophysical Journal Published on: 04/2020 YEAR: 2020 DOI: 10.3847/1538-4357/ab7b7a Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Magnetic Field Kinks and Folds in the Solar Wind Parker Solar Probe (PSP) observations during its first encounter at 35.7 R☉ have shown the presence of magnetic field lines that are strongly perturbed to the point that they produce local inversions of the radial magnetic field, known as switchbacks. Their counterparts in the solar wind velocity field are local enhancements in the radial speed, or jets, displaying (in all components) the velocity-magnetic field correlation typical of large amplitude Alfv\ en waves propagating away from the Sun. Switchbacks a ... Tenerani, Anna; Velli, Marco; Matteini, Lorenzo; eville, Victor; Shi, Chen; Bale, Stuart; Kasper, Justin; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Klein, Kristopher; 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/ab53e1 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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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; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5b15 |
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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 |
| 2019 |
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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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On slow solar wind with high Alfv\ enicity: from composition and microphysics to spectral properties Alfv\ enic fluctuations are very common features in the solar wind and are found especially within the main portion of fast-wind streams while the slow wind usually is less Alfv\ enic and more variable. In general, the fast and slow winds show many differences, which span from the large-scale structure to small-scale phenomena, including also a different turbulent behaviour. Recent studies, however, have shown that even the slow wind can sometimes be highly Alfv\ enic, with fluctuations as large as those of the fast wind. ... D’Amicis, Raffaella; Matteini, Lorenzo; Bruno, Roberto; Published by: Monthly Notices of the Royal Astronomical Society Published on: 3/2019 YEAR: 2018 DOI: 10.1093/mnras/sty3329 Astrophysics - Solar and Stellar Astrophysics; methods: data analysis; parker solar probe; Physics - Data Analysis; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus; Solar wind; Statistics and Probability; turbulence |
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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 |
| 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; Published by: Published on: 07/2013 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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